Discovery evolved out of a unique feature of early equitable pleading procedure before the English Court of Chancery: among various requirements, a plaintiff's bill in equity was required to plead "positions." These were statements of evidence that the plaintiff assumed to exist in support of his pleading and which he believed lay within the knowledge of the defendant. They strongly resembled modern requests for admissions, in that the defendant was required to plead only whether they were true or false. At some point between the reign of Elizabeth I (1558-1603) and the late seventeenth century, positions were gradually replaced by interrogatories—written questions which the defendant was required to truthfully respond to under oath in his answer to the bill based on information within his own personal knowledge as well as documents in his possession. But back then, interrogatories could only elicit admissible evidence (not the broader modern standard of "reasonably calculated to lead to the discovery of admissible evidence") and could only request evidence in support of the plaintiff's case, not either side's case (that is, they could not ask for evidence which the defendant intended to use in support of his defenses and was otherwise entirely irrelevant to the plaintiff's case). Even worse, this was purely a one-way procedure, because interrogatories could only be pleaded as part of a bill (a pleading "initiating" a suit in equity). A defendant who needed to obtain evidence in support of his defenses had to file a cross-bill against the plaintiff to plead his own interrogatories.