Complex sentence: Adisham Hall played host to many prominent personalities of the colony until, the retirement of Sir Thomas, when the house was sold to Sedawatte Mills and in 1961 it was purchased by the Roman Catholic Church converting it in to a monastery.
Split into simpler sentences: Adisham Hall played host to many prominent personalities of the colony until the retirement of Sir Thomas, after which it was sold to Sedawatte Mills. In 1961 it was purchased by the Roman Catholic Church and was subsequently converted to a monastery.