[4] Around 615 AD the current location of St. Cadwaladr's Church was established as royal monastery by the Kings of Gwynedd.

[5] King Cadfan ap Iago had been buried in the church, and his tombstone c. 634 is still on display today.

Then in the 15th century a stained glass window was added which is still in the church today after being restored in 1850.

The tombstone was inscribed c. 634:[8][5] Latin: CATAMANUS REX SAPIENTIS MUS OPINATISM US OMNIUM REG UM.English: King Cadfan, the Wisest and Most Renowned of All Kings.It was during the Tudor period that the church was given stained glass windows as a gift from the Meyrick family (Welsh: Meurig) of Bodorgan as thankfulness for the return of their son Owain Ap Meurig after fighting with Henry Tudor at the Battle of Bosworth (1485).

[11] An inscription for the c. 1485 (Tudor period) glass stained window reads:[10] Pray for the good estate of Meuric ap Llywelyn ap Hwlcyn esquire; Marged verch Ifan Fychan, Owain ap Meuric, Elen verch Robert, Who caused the window to be made.During 1860, a local family member in the vicinity Owen Fuller Meyrick donated a glass stained windows depicting the resurrection of Jesus, the healing of a beggar by Saint Peter and John outside the Beautiful Gate and Salome desiring Christ honour her sons.

Also, there is another memorial for Hugh Owen (English Civil War colonel Royalist) from 1660 in the chapel.

Another memorial for the reconstruction of the north chapel was made in 1801 by Owen Putland Meyrick (died 1825).