ith en yn , ▁active ▁in ▁the ▁middle ▁of ▁the ▁sixth ▁century . ▁ ▁Both ▁he ▁and ▁his ▁father ▁are ▁said ▁to ▁have ▁been ▁part ▁of ▁the ▁Christian ▁community ▁on ▁B ard sey ▁Island , ▁at ▁the ▁tip ▁of ▁the ▁L l <0xC5> <0xB7> n ▁Pen ins ula ▁in ▁north - west ▁Wales . ▁Some ▁of ▁his ▁sib lings ▁are ▁also ▁v ener ated ▁as ▁sain ts . ▁ ▁Tw r nog ▁is ▁comm emor ated ▁at ▁the ▁church ▁in ▁L land yr nog , ▁Den b igh shire , ▁in ▁north - east ▁Wales , ▁while ▁his ▁brother ▁T ud ur ▁( or ▁T ud yr ) ▁was ▁recorded ▁as ▁a ▁saint ▁from ▁Dar ow en , ▁Pow ys , ▁in ▁west ▁Wales . ▁His ▁sister , ▁March ell , ▁is ▁reported ▁to ▁have ▁established ▁Y str ad ▁March ell , ▁near ▁Wel sh pool ▁in ▁mid - W ales , ▁where ▁an ▁ab bey ▁( Str ata ▁Marcel la ) ▁was ▁later ▁built . ▁ ▁Comm em oration ▁Ty f ry dog ▁is ▁the ▁patron ▁saint ▁and ▁the ▁re put ed ▁founder ▁of ▁St ▁Ty f ry dog ' s ▁Church , ▁L land y f ry dog , ▁a ▁small ▁village ▁in ▁Ang les ey , ▁north ▁Wales . ▁The ▁tradition ▁is ▁that ▁he ▁established ▁the ▁church ▁in ▁about ▁ 4 5 0 . ▁No ▁part ▁of ▁a ▁building ▁from ▁that ▁period ▁surv ives ; ▁the ▁earliest ▁parts ▁of ▁the ▁present ▁structure ▁date ▁from ▁about ▁ 1 4 0 0