Complex sentence: Dysert O Dea Church stands on the site of an Early Christian monastery, which was founded by St Tola who died about 735 although most of the present buildings are from the 12th century.
Split into simpler sentences: Dysert O Dea Church stands on the site of an Early Christian monastery. The monastery was was founded by St Tola, who died about 735, although most of the present buildings are from the 12th century.