The bridges originally broke in 34 AD, and hadn’t been repaired by 1300. See Dante’s Inferno for details.
Meanwhile, in the Malebolge:
Malpeau: The last bridge is finally finished!
Katzenjammer: Aye! An’ a good strong job she looks like…
…’ere, what’s that light?
Malpeau: Only one thing casts a light that bright–
–an envoy from Heaven!
Malpeau: Hey! –We just finished rebuilding those!