Who was Hengest? A legend fragment that seems to be related to Beowulf suggests he was a banished chieftain. The Gildas-Bede-Historia Brittonum–The Anglo-Saxon Chronicle tradition would seem to confirm the latter. And that seems plausible; there is no point in moving across a sea unless there is a reason to leave home.
The easy connections end there, however. As vague as Gildas is about the dates when the first Germanic foederati arrived, he makes it perfectly clear that Hengest and his cohorts do come after the Romans leave (while Gwrtheyrn is overlord of Britain in fact, but that particular anachronism has been otherwise discussed). Gildas is here wrong. We know from the archeological and Rome’s historical evidence that there were foederati in Britain as early as 300. We also know that the last recorded chieftains were Fraomar and one Ansehis, a name easily miswritten as Anschis and from there possibly corrupted to Hengest. But I’ll get back to that.
Gildas wasn’t real big on names, so it should come as no surprise that he mentioned no additional Anglo-Saxons in his history. It’s disappointing, however, and makes for a difficult reconstruction of early post-Roman Britain. Added to that, the Germanic foundation legends were necessarily oral (Christianity in 616 would introduce writing for the first time), and oral legends about the history of a dynasty tend to follow a consistent pattern that makes for good reading but poor history.
The pattern works as follows. First the founder of the line is named and his traditional accomplishments recounted. Then history is really bent and twisted. Very little is usually known about a founder’s ancestors as anarchy tends to precede the foundation of a family, so the hole in the past is exploited. In order to add strength and prestige to a dynasty, any and all famous warriors and kings of the past might be added to the beginning of a lineage. So for instance if the U.S. had gained its independence in an oral climate and had decided on a monarchy we might have recorded that Miles Standish had been Washington’s father and Daniel Boone his grandfather. Pocahantas would have been named as his divinely inspired mother.
The Kentish royal line was known as the Oiscingas. Oisc was therefore the founder, and most likely was an historical figure. Nothing before that can be believed, however. That point must be clear. Hengest, Horsa, and AEsc could possibly have been Oisc’s ancestors, but only if they had been noteworthy leaders in their own right who had been remembered for one or two accomplishments. That any of those men were ancestors to Oisc is about as likely as Standish being a real ancestor of George Washington.
What do we know of the Germanic people in Kent before Oisc? If they are otherwise identifiable (which is unlikely), Hengest was likely the fourth century figure Ansehis: It seems reasonable that there was a prominent chieftain in Kent during the mid-fifth century rebellion, and AEsc is the most likely candidate. If Oisc was the grandfather of AEthelberht (another assumption), he was active in the middle of the sixth century. Reasonably he could have been contemporary to Gwrtheyrn.