Paleologi; Italian: Paleologo), also called Palaiologos, Palaeologus and Paleologue, were a noble family from Pesaro in Italy who later established themselves in England in the 17th century.

With the exception of a single figure in their purported genealogy, a son of Thomas by the name of John who is absent in contemporary sources, their claimed line of descent can be verified through documents at Pesaro.

In November 1460, the highest-profile Byzantine exile of them all, Thomas Palaiologos, younger brother of the final emperor Constantine XI, arrived in Rome, hoping to convince Pope Pius II to call for a crusade so that the empire could be restored.

[12] The Paleologus family, attested as living in Pesaro, Italy, from the early 16th century onwards, claimed descent from a third son of Thomas Palaiologos, called John.

It appears that much of it was rewritten by an editor at a later date and the timeline the works provide is somewhat questionable, having Thomas's wife Catherine give birth to one of their children at the age of 65.

[14] The earliest source unrelated to the Paleologi of Pesaro themselves that mentions a son of Thomas by the name John is the writings of the Greek scholar Leo Allatius.

Allatius wrote in 1648, too late for his works to act as independent evidence for the descent of the Paleologus family, but he 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.

[19] This acceptance stands in contrast to the fates of other would-be Palaiologoi in the 17th century, such as a "Theodore Palaeologus" who lived in Prague in 1603, who were convicted as forgers for their supposed claims.

Tradition has it that during the Greek War of Independence (1821–1829), over a century after the Paleologi disappeared from history, a delegation was sent by the provisional government in Athens to find living descendants of the old imperial family.

The letter supposedly requested that if that was the case, the head of the family should be provided with the means of returning to Greece, with the trip paid for by the Greek government.

[21] The 19th-century English priest Arthur Penrhyn Stanley claimed that the delegation had intended to make the head of the family, had one been found, into the sovereign of Greece.

[23] English historian William Henry Hamilton Rogers wrote in 1890 in regards to this possibility, "how strange would have been the circumstance had such an undoubted descendant been discovered, and the imperial eagle arisen like a phoenix from the ashes of time, and strove to consolidate the shifting fortunes of this heroic and struggling people".

[24] An article from 11 May 1913 in The San Francisco Call, titled Find in England, Traces of Dynasty, Once Ruled the World, identified the Paleologus family as "by descent rightful rulers of the empire of the east" and stated that there may yet be more research to be done in an attempt to track down potential descendants of the family "if fortune's whirligig should bring about circumstances requiring that the hereditary emperor of the east should be sought out to reign once more in Constantinople".

[25] As late as 1940, English historian Sir Stanley Casson described Theodore Paleologus, the family's most famous member, as the "last recorded heir to Byzantium".

[26] Beginning with English historian Steven Runciman's 1965 book The Fall of Constantinople, in which the double-headed eagle on the tombstone of Theodore is described as having "no business to be there", a number modern scholars have dismissed the later Paleologi as impostors, mainly on account of the lack of evidence for John's existence.

[34] In 1578, Leonidas and Scipione lived together with Camilio's young son, Theodore, and found themselves embroiled in a scandal as they were convicted for the attempted murder of Leone Ramusciatti, a man who was also originally of Greek descent.

[37] Ultimately, Theodore failed to kill Antelminelli, and perhaps because he wanted a safer and more stable profession (he was around 40 years old), he stayed in England for the rest of his life, first entering into the service of Henry Clinton, the Earl of Lincoln.

[41] Villiers was assassinated soon thereafter, however, and Theodore was instead invited to stay with Sir Nicholas Lower, a rich Cornish squire, at his home in Landulph, Cornwall,[42] called Clifton Hall.

Theodore Junior supported the Roundheads, who meant to end absolute monarchy in Britain, and did not survive the war, probably dying of camp fever during the early stages of the long Siege of Oxford.

[46] He quickly became one of the elite on the island, cultivating cotton or sugar and possibly pineapples and was highly influential in the affairs of the local St. John's Parish Church.

Theodore's coat of arms prominently displays a double-headed eagle, harkening back to the old emperors, but also incorporates two towers, the meaning of which is unknown.