The Testimonium Flavianum is a famous- or infamous- passage from Josephus that on its face appears to corroborate the existence of Jesus in a non-Christian ancient source. The TF was accepted as genuine for centuries until the Rationalists got a hold of it. The assertion that it is a complete forgery is common and if hyper-skeptics could get away with it, that’s where they’d leave it. Unfortunately, this is difficult, and the consensus is that it is an interpolation, and as such provides, minimally, evidence of Jesus’ existence.
If that is the consensus it may be a surprise to hear someone (me) suggesting that it is neither forgery nor interpolation, but rather genuine and authentic. As I am a real free thinker, those who know me I don’t think are surprised at all. 🙂