Killenny was founded some time between 1162 and 1165 by Dermot
O’Ryan, liegeman of Dermot Mac Murrough, the king of Leinster.
The house was dedicated to St. Mary and St. Benedict. It seems
the monks were not officially recognized as Cistercian until 1185,
when the abbey was affiliated to Jerpoint.
It has been argued
that the monks were considered Benedictine up until the
date of their affiliation with Jervaulx, but this hypothesis
has been refuted and the
history of the abbey in these years remains obscure. Killenny
Abbey was inadequately endowed from the start and in the early
century it was said to have been too poor to survive; it was burdened
with debts and unable to provide hospitality. In 1202, Abbot Thomas
monks had their possessions confirmed and were granted the
right to elect their own abbot. The monks were involved in the ‘riot
of Jerpoint’ (1217) and when the abbey was visited by
the abbot of Froidmont it was discovered that Killenny was
so much in
debt that it could no longer continue. Thus, in July 1227 it was
united with Duiske (Graiguenamanagh)
and Killenny subsequently became a grange of Duiske (Graiguenamangh).
sparked off a long running dispute between Jerpoint and Graiguenamanagh
over the ownership of the abbey.
In 1525 the grange was granted
to Charles Cavenagh for sixty-one years. He was still in possession
in 1548 although it is not known whether any monks were with
Nothing now remains of the abbey.