Sir Patrick Houstoun and his family were principal patrons and regular worshipers at the parish church, which at that time was Roman Catholic. When the knight died after many years as laird of the family estate, which comprised the entire parish, he was honored with burial in the Houstoun Church. This was in 1450 and his wife died six years later and must have been buried at his side.

Some 344 years later, in 1794, one writer reports that two faded oil color pictures still hung on the walls of the church. One showed Sir Patrick in full armor "like that of a Knight Templar." The other was of his wife, Lady Mary Colquhoun Houstoun.

Patrick was succeeded by his son, Sir John Houstoun, in the reign of James II. Those were turbulent times for the Stewart kings and must have been difficult for the Houstouns as loyal friends and supporters of this royal line. Four of the kings in succession died violently. James I was assassinated in 1437. James II was killed in 1460 when one of his crude cannon, just coming into use at that time, exploded. James III was murdered in 1488 and his son, James IV, was killed in battle.

Heirs of these sovereigns, almost without exception, inherited the throne while still in childhood. This made is necessary for government to be carried on by rival regents, adding fuel to violence and turmoil.

It is not known how Sir John met his death, but he lived to rule the barony only six years and died in the same year as his mother. He is remembered chiefly by a monument of stone part of which is preserved to this day and can be seen by visitors to the Houston-Kilallan Parish church in Renfrewshirc.