Lamberton House was built during the reign of King James by Charles Lambert, Earl of Cavan.  He died in 1660 and is buried in St Patrick’s Cathedral.  Richard 2nd, Earl of Cavan, his son, succeded him and lived there until his death.  He was buried in St Peter's Church Maryburough.
There were a lot of owners of the estate over the years and eventually it was sold by Rev. John Tydd Moore to James Butler.   It was purchased by the Sweetman family from Killkenny.  The Sweetmans had four daughters and two sons.  Micheal was killed in World War 1.  Elinor Sweetman, who was a poet, lived with her sister Gertrude.  Eleanor died in 1936 and was buried in
the grounds of the Church of the Holy Cross, Ratheniska and in 1941 Gertrude was buried there.
The Sweetmans donated the Stations of the Cross to  the Church of Ratheniska.  They also donated the stained glass window behind the High alter in the old Church, Porthlaoise.  Eleanor left the estate to her niece Marie Louse who married Count De Meeus, a Belgiun.  There are about 500 acres in the Lamberton Estate.  The house now stands in ruins.