Probably not really what you're looking for, but worth a shot:

The books 2 Kings, 2 Chronicles, and Ezra all contain narratives about the Babylonian Captivity. They're extremely religious in nature, and have likely been altered over the millenia (making their historicity debatable to say the least), but slave narratives nonetheless.

EDIT: I'm not sure if I should provide a source about the likelihood of biblical texts being altered or edited throughout history. I've always considered it common enough knowledge, but somebody let me know and I'll seek a supporting text (or if somebody has one on hand, that works, too).

St. Patrick of Ireland's Confession, written around 450 CE, mentions how he was taken captive and enslaved when he was sixteen, but the narrative is very scant about details.