Among Christian writers, since the 1st century AD, "the Bosom of Abraham" has gradually ceased to designate a place of imperfect happiness, especially in the Western Catholic tradition, and it has generally become synonymous with Christian Heaven itself, or the Intermediate state. Church fathers sometimes used the term to mean the limbo of the fathers, the abode of the righteous who died before Christ and who were not admitted to heaven until his resurrection. Sometimes they mean Heaven, into which the just of the New Covenant are immediately introduced upon their demise. Tertullian, on the other hand, described the bosom of Abraham as that section of Hades in which the righteous dead await the day of the Lord.