The Paleologus family in Pesaro, attested from the early 16th century onwards, claimed descent from 'John Palaiologos', a purported third son of Thomas Palaiologos. Their genealogy mainly derives from the tombstone of Theodore Paleologus (d. 1636), which lists Theodore's male-line ancestors five generations back, reaching Thomas. With the sole exception of Thomas's purported son John, the existence of the rest of Theodore's immediate ancestors can be verified through records at Pesaro. The earliest record of John's existence other than Theodore's tombstone are the writings of the Greek scholar Leo Allatius, who wrote in 1648, too late for his works to be considered independent evidence. Allatius was the keeper of the Vatican Library and would have had access to its vast collection of books and records and might have deduced his findings from there.' As such, it is possible that Allatius had access to earlier documents, now lost, which would have proven the legitimacy of the Pesaro line. Allatius gives the sons of Thomas as "Andrea, Manuele and Ioanne".' It would be difficult to explain why Allatius, a respected scholar, would simply make up a member of an ancient dynasty. The absence of any mentions of John Palaiologos in contemporary sources means that the Paleologus family's status as genuine male-line descendants of the last few Byzantine emperors can not be proven, but it is not impossible. None of their own contemporaries appear to have doubted their imperial descent.'