In Dialogue with Trypho, an early Christian text, Justin Martyr and a Jew named Trypho discuss the nature of the soul and its interaction with God. After talking a bit about if animals could see God and if that was any different than humans, this conversation happens (translation taken from here):
[Trypho asked,] "'What, then, is the advantage to those who have seen [God]? or what has he who has seen more than he who has not seen, unless he remember this fact, that he has seen?'
"'I cannot tell,' I [Justin Martyr] answered.
"'And what do those suffer who are judged to be unworthy of this spectacle?' said he.
"'They are imprisoned in the bodies of certain wild beasts, and this is their punishment.'
This seems like a really bizarre conclusion to me, yet Trypho seems to take it in stride, moving on to his next argument. Why would Justin Martyr assert that those who see God and yet were unworthy would become imprisoned in the bodies of certain wild animals? Was this a commonly held belief in his lifetime (in the years A.D. 100–165)?