Interesting- he's the one who had his half-brother Giulio's eyes put out when a woman they both desired (Angela Borgia, cousin of Lucrezia) admired them.I've finished "The Cardinal's Hat: Money, Ambition, and Everyday Life In the Court of A Borgia Prince" by Mary Hollingsworth (267pgs, 2004). An interesting look at the life of Ippolito d'Este, 2nd son of Lucretia Borgia, most derived from account books kept during his quest for his Cardinal's Hat.
He features in Shellabarger's wonderful novel, The Prince of Foxes