Me. Justice Maeshall
delivered the opinion of the Court.
The question for decision is whether petitioner has made a sufficient showing in support of his claim to United States citizenship to entitle him to a de novo judicial determination of that claim under § 106 (a) (5) (B) of the Immigration and Nationality Act, 8 U. S. C. § 1105a (a)(5)(B) (1976 ed.).
I
In 1967, the Immigration and Naturalization Service began deportation proceedings against petitioner, Joseph Agosto, by issuance of a show-cause order charging that he was dfeportable as an alien who had unlawfully entered the United States. App. 4-6. Petitioner opposed deportation, claiming that he was born in this country and therefore is a citizen of the United States not subject to deportation. Over the course of several years, a series of hearings were held before an Immigration Judge, at which the Service presented documentary evidence in an effort to show that petitioner was born in Italy in 1927 of unknown parents, placed in a foundling home there, and ultimately adopted by an Italian couple. Petitioner presented testimony from himself and several other witnesses to show that he was born in Ohio of an Italian mother and sent to Italy at an early age to reside with the aforementioned couple.
In April 1973, the Immigration Judge issued the deportation order challenged here, rejecting the evidence tendered by petitioner and his witnesses that he was born in the United States. App. 23-59. The Board of Immigration Appeals affirmed. It noted that, “[i]f believed, the testimony of [petitioner's witnesses] clearly refutes the Service's otherwise strong documentary demonstration of [petitioner's] alienage” and that “[i]t is not beyond the realm of possibility that [petitioner's] claim to United States citizenship is legitimate.” Pet. for Cert. viii. The Board nevertheless accepted the Immigration Judge's credibility determinations and found that the “Service’s case as to alienage is clear, convincing and unequivocal.” Id., at xi.
Agosto petitioned for review of the Board’s decision in the United States Court of Appeals for the Ninth Circuit pursuant to § 106 of the Act, and claimed that, pursuant to § 106 (a) (5), he was entitled to a de novo hearing in District Court to determine whether he was a United States citizen. Section 106 (a)(5) provides that, whenever a petitioner “claims to be a national of the United States and makes a showing that his claim is not frivolous,” the court of appeals is to transfer the proceedings to the district court for a hearing on that claim if “a genuine issue of material fact as to the petitioner’s nationality is presented.” When no genuine issue of material fact is presented, the court of appeals has authority to “pass upon the issues presented.”
The Court of Appeals, with one judge dissenting, refused to transfer the case to the District Court for a de novo hearing on petitioner’s citizenship claim, and affirmed the deportation order. Pet. for Cert, i; affirmance order, 549 F. 2d 806. It held that “[t]he evidence presented to the immigration judge does not disclose a colorable claim to United States nationality.” Pet. for Cert. ii. Further, the Court of Appeals apparently concluded that in order to obtain a de novo hearing petitioner was required to present “substantial evidence” in support of his citizenship claim and that he had failed to do so. Ibid. The dissenting judge, while acknowledging that as a factfinder she would not have credited petitioner’s testimony, stated that “I do not believe our legally assigned role includes a decision on credibility, and, on that basis, I am unable to say that petitioner’s evidence, if believed, would not present a colorable claim to American citizenship.” Ibid.
We granted certiorari, 434 U. S. 901 (1977), to consider the proper construction of § 106 (a) (5) (B), and we now reverse.
II
In 1961, Congress enacted § 106 of the Immigration and Nationality Act, 8 U. S. C. § 1105a (1976 ed.), in order “to create a single, separate, statutory form of judicial review of administrative orders for the deportation ... of aliens from the United States.” H. R. Rep. No. 1086, 87th Cong., 1st Sess., 22 (1961). This statutory provision eliminated district court review of deportation orders under § 10 of the Administrative Procedure Act, 5 U. S. C. §702 (1976 ed.), and replaced it with direct review in the courts of appeals based on the administrative record. Congress carved out one class of cases, however, where de novo review in district court would be available: cases in which the person subject to deportation claims to be a United States citizen.
In carving out this class of cases, Congress was aware of our past decisions holding that the Constitution requires that there be some provision for de novo judicial determination of claims to American citizenship in deportation proceedings. See H. R. Rep. No. 1086, supra, at 29; H. R. Rep. No. 665, 87th Cong., 1st Sess., 15 (1961). In Ng Fung Ho v. White, 259 U. S. 276, 284 (1922), the Court observed:
“Jurisdiction in the executive to order deportation exists only if the person arrested is an alien. ... To deport one who . . . claims to be a citizen, obviously deprives him of liberty, . . . [and] may result also in loss of both property and life; or of all that makes life worth living.”
We therefore held that a resident of this country has a right to de novo judicial determination of a claim to United States citizenship which is supported “by evidence sufficient, if believed, to entitle [him] to a finding of citizenship.” Id., at 282. See also United States ex rel. Bilokumsky v. Tod, 263 U. S. 149, 152-153 (1923). In Kessler v. Strecker, 307 U. S. 22, 34-35 (1939), we reaffirmed that holding and indicated in dictum that judicial determination of citizenship claims is required where “substantial evidence” is presented to support the citizenship claim.
In the instant case, the court below stated that petitioner failed to satisfy the standard of Kessler v. Strecker, supra; the court thus implicitly held that the standard of “substantial evidence” had been incorporated into § 106 (a)(5)(B). Pet. for Cert. ii. We disagree. Although Congress intended § 106 (a)(5) to satisfy any constitutional requirements relating to de novo judicial determination of citizenship claims, supra, the statute clearly does not restrict de novo review to cases in which the “substantial evidence” test is met. Rather than incorporating the specific language of Kessler into the statute, as it easily could have done, Congress chose instead to require hearings where there is “a genuine issue of material fact” — a standard that is different from but as familiar as the substantial-evidence standard.
This statutory language is virtually identical to that embodied in Fed. Rule Civ. Proc. 56, which governs summary judgment motions. Under Rule 56, district court litigants opposing summary judgment have a right to a trial whenever there exists a “genuine issue as to any material fact.” We may reasonably assume that, in using the language from Rule 56 as the standard for granting de novo district court hearings on citizenship claims, Congress intended the language to be interpreted similarly to that in Rule 56. “'[W]here words are employed in a statute which had at the time a well-known meaning at common law or in the law of this country they are presumed to have been used in that sense unless the context compels to the contrary.’ ” Lorillard v. Pons, 434 U. S. 575, 583 (1978), quoting Standard Oil v. United States, 221 U. S. 1, 59 (1911). The Court of Appeals decision in this case, to the extent that it holds de novo review to be required only where the petitioner presents substantial evidence in support of his claim to citizenship, is thus contrary to the plain language and clear meaning of the statute.
Nor does anything in the legislative history indicate that Congress intended to require de novo judicial determination of citizenship claims only when such determinations would be compelled by the Kessler “substantial evidence” standard. Although there are references in the legislative history suggesting that a claim to citizenship must itself be “substantial,” these statements are not amenable to the interpretation that substantial evidence is required in support of the claim before a judicial hearing would be provided. See, e. g., H. R. Rep. No. 1086, supra, at 29; H. R. Rep. No. 565, supra, at 5. While Congress in enacting § 106 sought to “expedite the deportation of undesirable aliens by preventing successive dilatory appeals to various federal courts,” Foti v. INS, 375 U. S. 217, 226 (1963), this concern hardly justifies the assumption that Congress intended to impose a steep hurdle to judicial determination of citizenship claims. None of the abuses of judicial review catalogued by Congress in the Committee Reports related to citizenship claims. See H. R. Rep. No. 565, supra, at 7-13. Rather, Congress was primarily concerned with the filing of repetitive petitions for review and with frivolous claims of impropriety in the deportation proceedings. See, e. g., H. R. Rep. No. 1086, supra, at 23, 33; 107 Cong. Rec. 19650 (1961) (remarks of Sen. Eastland); 105 Cong. Rec. 12724 (1959) (remarks of Rep. Walter).
Since summary judgment principles are controlling here, it follows that a court of appeals cannot refuse to allow a de novo review of a citizenship claim if the evidence presented in support of the claim would be sufficient to entitle a litigant to trial were such evidence presented in opposition to a motion for summary judgment. More specifically, just as a district court generally cannot grant summary judgment based on its assessment of the credibility of the evidence presented, see Poller v. Columbia Broadcasting System, Inc., 368 U. S. 464, 467-468 (1962); 6 J. Moore, Federal Practice ¶ 56.02 [10], p. 56-45 (2d ed. 1976), so too a court of appeals is not at liberty to deny an individual a de novo hearing on his claim of citizenship because of the court’s assessment of the credibility of the evidence, see Pignatello v. Attorney General of the United States, 350 F. 2d 719, 723 (CA2 1965). Particularly where the evidence consists of the testimony of live witnesses concerning material factual issues, it will seldom if ever be appropriate to deny a de novo hearing, since “[i]t is only when the witnesses are present and subject to cross-examination that their credibility and the weight to be given their testimony can be appraised.” Poller v. Columbia Broadcasting System, Inc., supra, at 473.
Ill
Applying the appropriate standard to the record in this case, it is apparent that the Court of Appeals erred when it failed to transfer the case to the District Court for a de novo hearing. The Service’s proof that .petitioner is not a United States citizen would certainly be sufficient, if uncontradicted, to establish his birth in Agrigento, Italy, in July 1927. However, the evidence adduced by petitioner to support his claim of American citizenship creates “genuine issue [s] of material fact” that can only be resolved in a de novo hearing in' the District Court.
Petitioner acknowledges that the Service’s documentary proof pertains to him. This proof includes an entry from the city of Agrigento registry of births for 1927 relating that a 75-year-old handy woman appeared before the registrar and declared that “at 4:00 a. m. on the 17th day of [July] in a house situated in Via Oblati, of a woman who does not want to be named, a male child was born, which she presents to me and to whom she gives the first name of Vincenzo and the surname of Di Paola.” Record 667. The city registry also indicates that the child was sent to a foundling home. In addition, the foundling home’s registry indicates that a Vincenzo Di Paola was born on July 16,1927, and was consigned to Crocifissa Porello, petitioner’s adoptive mother and wife of Pietro Pianetti, petitioner’s adoptive father, on August 26, 1927. The last piece of documentary evidence is a translation from the foundling home record showing that Vincenzo Di Paola was baptized on July 18, 1927.
Petitioner claims, however, that the records regarding Vincenzo Di Paola were made at the request of his maternal grandfather to hide the true facts of his illegitimate birth in the United States. Petitioner’s evidence in support of his claim to United States citizenship consisted of his own testimony and that of his adoptive parents, Crocifissa and Pietro Pianetti, and his alleged half brother, Carmen Ripolino.
According to the testimony of the Pianettis, petitioner was the illegitimate son of Crocifissa Pianetti’s sister, Angela Porello, who left her Italian husband and two daughters in 1921 to move to the United States with her cousin Giacomo Ripolino. Through correspondence with Angela, the Pianettis learned in about 1925 that petitioner had been born, that his father was Salvatore Agosto, and that Angela had at least two other children, including Carmen Ripolino. According to the Pianettis, petitioner was sent to live with them and with Angela’s parents because Angela could not care for petitioner in Ohio. The Pianettis testified that petitioner was never in the foundling home, but that the documents presented by the Service concerning petitioner’s birth in Italy were created by Angela’s father to hide the fact that petitioner was his illegitimate grandson.
Carmen Ripolino corroborated the testimony of the Pianettis in important respects. He testified that his mother was Angela Porello, and that she told him when he was a child that he had two half sisters in Italy and a half brother whom she had sent there to live with her mother. Although Carmen Ripolino admitted having no independent knowledge that petitioner was the brother who had been sent to Italy, his testimony corroborated that of the Pianettis that Angela Porello gave birth to a son in this country whom she sent to Italy to live with relatives.
Petitioner’s testimony was only partially consistent with that of his witnesses. Because-he possessed a birth certificate belonging to one Joseph Agosto, born in Cleveland in 1921, which had allegedly been sent to petitioner in Italy by another American relative between 1948 and 1950, petitioner maintained for a time that he was that Joseph Agosto, the son of Salvatore Agosto and his wife Carmela Todaro. The birth certificate had not actually been issued, however, until sometime after petitioner claimed to have received it. At the same time petitioner also testified that he had been told that his mother’s name was Angela Porello and that he lived with his grandfather and the Pianettis after coming to Italy as a small boy. Petitioner acknowledged that he had been known by different names at different times.
There is no doubt that petitioner has not told one story consistently throughout his deportation hearings and has attempted to establish his citizenship by relying on any possible shred of evidence. Nor is there any doubt that petitioner has told different stories about his past to diffeient courts. But it is noteworthy that, starting in his- first deportation hearing,, petitioner has acknowledged that he is not certain of his true parental origins, and that he-had been told that his mother was Angela Porello. And, given the obvious confusion and uncertainty surrounding the circumstances of ■ petitioner’s birth (under either the Service’s theory or that of petitioner), it is hardly surprising that petitioner cannot say with any degree of certainty who his true parents might have been.
We need not decide whether petitioner’s testimony, standing alone, is so inherently incredible in light of its internal inconsistencies as to justify denial of de novo judicial review of the citizenship claim. In this case, the citizenship claim is supported by the testimony of three witnesses whose story, while highly unusual, certainly cannot be rejected as a matter of law. Their disputed testimony concerning petitioner’s birth in this country and subsequent upbringing in Italy is in most respects no more unusual than their unchallenged testimony concerning other aspects of this family’s relations. To accept the present claim to United States citizenship, the District Court would need only to believe that petitioner was born to Angela Porello in Ohio in the mid-1920’s; that he was sent by her to live with the Pianettis in Italy; and that Angela’s father had the birth records in his native town falsified to prevent public knowledge of the birth of an illegitimate child to his daughter while still permitting him and other members of his family to raise the child. These events, while out of the ordinary, are not so extraordinary as to compel disbelief in their occurrence. Even the Board of Immigration Appeals, which rejected petitioner’s claim of citizenship, stated that “[i]t is not beyond the realm of possibility that [petitioner’s] claim to United States citizenship is legitimate.” Pet. for Cert. viii.
Since the documentary evidence submitted by the Service would be refuted by the testimony of petitioner’s witnesses if that testimony were accepted by the trier of fact, ibid., there is plainly a genuine issue of material fact for the District Court on the question of petitioner’s citizenship. Although as the trier of fact the District Court might reject the testimony of these witnesses because of their interest in the outcome, that determination has been committed by Congress to the district courts by § 106 (a) (5) (B) of the Act and not to the courts of appeals. The decision of the Court of Appeals must therefore be reversed and the case remanded for proceedings consistent with this opinion.
Reversed and remanded.
After petitioner’s first set of hearings, an Immigration Judge issued a deportation order, App. 18, which petitioner then appealed to the Board of Immigration Appeals. The Board remanded to permit the Immigration Judge to consider petitioner’s claim that he was entitled to relief from deportation pursuant to § 241 (f), 8 U. S. C. § 1251 (f) (1976 ed.), as the husband of a United States citizen, but did not consider petitioner’s other challenges to the finding that he was deportable. App. 19-20. At the hearing on remand, the Service lodged an additional charge against petitioner alleging that he was deportable because he had been convicted of crimes of moral turpitude. The Immigration Judge adhered to his finding that petitioner was deportable and not entitled to relief under § 241 (f). Record 677-691. On petitioner’s second appeal, the Board again remanded for a further determination of petitioner’s eligibility for § 241 (f) relief and to permit petitioner to produce certain witnesses in support of his claim to United States citizenship. Record 628-633. The deportation order challenged here was issued after petitioner’s third set of hearings, App. 23-59, and the Board affirmed the order. Pet. for Cert, iv-xiii.
Section 106 (a) (5), as set forth in 8 U. S. C. § 1105a (a) (5) (1976 ed.), provides:
“[W]henever any petitioner, who seeks review of an order under this section, claims to be a national of the United States and makes a showing that his claim is not frivolous, the court shall (A) pass upon the issues presented when it appears from the pleadings and affidavits filed by the parties that no genuine issue of material fact is presented; or (B) where a genuine issue of material fact as to the petitioner’s nationality is presented, transfer the proceedings to a United States district court for the district where the petitioner has his residence for hearing de novo of the nationality claim and determination as if such proceedings were originally initiated in the district court under the provisions of section 2201 of title 28. Any such petitioner shall not be entitled to have such issue determined under section 1503 (a) of this title or otherwise . . . .”
Prior to 1961, there was no specific statutory authorization for judicial review of deportation orders. For many years, habeas corpus had been the exclusive judicial remedy for challenging such orders, see Heikkila v. Barber, 345 U. S. 229, 235 (1953), but in 1955, we held that aliens could also obtain review of deportation orders in actions for declaratory and injunctive relief in district court under § 10 of the Administrative Procedure Act, 5 U. S. C. §702 (1976 ed.), Shaughnessy v. Pedreiro, 349 U. S. 48.
In addition to showing the existence of a “genuine issue of material fact” as to his nationality, a petitioner must demonstrate that his citizenship claim is not “frivolous” to obtain a de novo hearing. § 106 (a)(5). The “frivolousness” standard apparently refers to the merits of the legal theory underlying the citizenship claim. A “frivolous” claim would be analogous to one that could not survive a motion to dismiss for failure to state a claim upon which relief can be granted under Fed. Rule Civ. Proc. 12 (b) (6). No one has suggested that the legal theory underlying petitioner’s claim to American citizenship — that he was born in this country — is frivolous.
In addition to holding that petitioner had not satisfied the standard of Kessler v. Strecker, the Court of Appeals held that petitioner had not made a “colorable” claim to United States citizenship. The dissenting judge stated that she was unable to say that petitioner’s claim was not “colorable.” The term “colorable” appears nowhere in the statute, and neither opinion hints at its derivation. We cannot tell whether, by use of the word “colorable,” the Court of Appeals was applying the proper standard as set forth in § 106 (a) (5); if it was applying that standard, we believe it did so erroneously. See Part III, infra.
None of the other Courts of Appeals to apply the standard have held that “substantial evidence” is necessary to trigger de novo review under §106 (a)(5)(B). Instead, they have all indicated, although with some variation in language, that the appropriate standard is whether there is a genuine issue of material fact as to petitioner’s alienage. See Olvera v. Immigration & Naturalization Service, 504 F. 2d 1372, 1375 (CA5 1974); Rassano v. Immigration & Naturalization Service, 377 F. 2d 971, 972 (CA7 1966); Maroon v. Immigration & Naturalization Service, 364 F. 2d 982, 989 (CA8 1966); Pignatello v. Attorney General of the United States, 350 F. 2d 719, 723 (CA2 1965).
Section 106 was designed to minimize dilatory and repetitious litigation of deportation orders in several key respects. First, § 106 (c) precludes consideration of petitions for review or for habeas corpus where the validity of the deportation order “has been previously determined in any civil or criminal proceeding, unless the petition presents grounds which the court finds could not have been presented in such prior proceeding, or the court finds that the remedy provided by such prior proceeding was inadequate or ineffective to test the validity of the order.” 8 U. S. C. § 1105a (c) (1976 ed.). Second, § 106 (a)(1) mandates that all petitions for review must be filed within six months of the date of the final deportation order. 8 U. S. C. § 1105a (a)(1) (1976 ed.). Finally, the statutory review proceeding replaces review in the district court under § 10 of the Administrative Procedure Act, 5 U. S. C. §702 (1976 ed.), with review directly in the courts of appeals. 8 U. S. C. § 1105a (a) (1976 ed.). See supra, at 752-753.
Petitioner and the Pianettis testified that the name Vincenzo Di Paola was probably chosen because July 17 was the feast day for Saint Vincent.
Salvatore Agostb was sometimes referred to in the deportation proceedings as Arcángelo Agosto. Petitioner claimed they were different names for the samé man who used one ¡name with his wife, Carmela'Todaro, and one ■name with Angela Porello.
Petitioner maintained, in connection with-' a suit to decl&ré his third wife his lawful wife, that he had been only 17 at the time of an earlier ni'ártiage in 1944, though in the-deportation proceedings he claimed to have beOn bom no later than 192§. In an effort to obtain leniency at his 'sentencing for falsification of papers in connection with a Federal Housing Administration loan, petitioner permitted his attorney to represent to the. court that petitioner had no- prior convictions; even though he did at that time have a criminal record in Italy.-
For example, Carmen Ripolino testified that he did not know who his father was, and that he had two birth certificates, one showing his father as Giacomo Ripolino (the man who brought Angela Porello to this country) and a second showing his father to be one Charles Litizia. In addition, the Pianettis testified to the varied relationships Mrs. Pianetti’s sister, Angela Porello, maintained with different men and to her departure from Italy with one of those men, leaving behind a husband and two daughters. Although the Service may not have challenged this other testimony because it was immaterial to the issue of petitioner’s citizenship, its lack of materiality and its unflattering character also suggest that the witnesses would have had no reason to testify to those events if they had not occurred.
Since only the registrar signed the entry in the registry of births regarding the birth of Vincenzo Di Paola and the witnesses who were present were unable to write and only had the document read to them, it is certainly not entirely implausible that Angela’s father was able to have that record and the notation at the foundling home falsified.