I continue to be astounded by how many people just can't pronounce my name correctly. I am named for one of the 12 Apostles, 3 syllables, so it shouldn't be that hard.
Thaddeus? Do you count the replacement? If so, then I could ask: Matthias?
You say it's 3 syllables, so you can eliminate Peter, John, Matthew, Thomas, Bartholomew, James, James, Andrew, Simon, Philip
I'm a big fan of naming after the Apostles. Unfortunately I only had 2 boys (but 7 girls!) And the first was the oldest, and for that, I went by the Catholic custom of naming the first son "Dominic" rather than the competing custom of naming him "Joseph". Then there's the more worldly custom of naming him after yourself -- didn't do that either.
He got an Apostolic middle name though. But actually that middle name goes WAY back in my family, to my Great-Grandfather at least. He's at least the 5th in his line to bear that middle name.