' s ▁life ▁thanks ▁to ▁a ▁manuscript ▁written ▁in ▁ 8 8 4 ▁by ▁a ▁Land é ven ne c ▁mon k . ▁ ▁Paul ▁Aur éli en ▁was ▁born ▁in ▁Wales ▁in ▁around ▁ 4 9 0 , ▁and ▁educated ▁at ▁the ▁Saint ▁Il t ud ▁school . ▁He ▁was ▁ord ained ▁as ▁a ▁priest ▁and ▁in ▁ 5 2 5 ▁left ▁Wales ▁for ▁the ▁continent ▁with ▁a ▁dozen ▁compan ions . ▁He ▁land ed ▁at ▁the ▁I le ▁d ' O u ess ant ▁and ▁pre ached ▁along ▁the ▁north ▁Fin ist ère ▁coast ▁up ▁to ▁the ▁Î le ▁de ▁B atz . ▁ ▁According ▁to ▁legend , ▁he ▁helped ▁free ▁the ▁Î le ▁de ▁B atz ▁from ▁a ▁drag on ▁which ▁was ▁terror ising ▁the ▁local ▁population . ▁ ▁The ▁c athedral ▁replaced ▁an ▁earlier ▁roman es que ▁bas il ica ▁founded ▁by ▁Bishop ▁Ham an ▁and ▁was ▁built ▁in ▁various ▁stages . ▁ ▁The ▁nave , ▁west ▁fa ç ade ▁and ▁the ▁south ▁por ch ▁date ▁to ▁the ▁ 1 3 th ▁century ▁and ▁the ▁bishop ric ▁of ▁Bishop ▁Des ilon , ▁whilst ▁the ▁cho ir ▁and ▁tr anse pt ▁date ▁to ▁the ▁early ▁ 1 5 th ▁century . ▁The ▁building ▁was ▁completed ▁in ▁the ▁second ▁half ▁of ▁the ▁ 1 6 th ▁century . ▁ ▁Bu ilt ▁on ▁the ▁site ▁of ▁an ▁ancient ▁Roman ▁church , ▁some ▁v estig es ▁of ▁which ▁still ▁exist . ▁This ▁great ▁monument ▁has ▁been ▁constructed ▁in ▁several ▁stages . ▁The ▁present