Founded by St. Fintan (d.603), Clonenagh was the most important monastery of ancient Leix. It located on the Slige Dala (road of the assemblies) ensured its importance in early medieval Ireland. O’Mores, descendants of the Loigis kings were the patrons of Clonenagh upto the sixteenth-century, and it was the monastic home of Oengus the Celi De (see Coolbangher). The Book of Leinster or Lebar na Nuachongbala started life here before moving to Oughaval near Stradbally. Today there you will see two graveyards, the ruins of an early church and a penny tree that collapsed recently.
