During the Middle Ages Scotland’s Stewart kings, James I to James V, had a close connection with St Giles’ and attended Roman Catholic Masses here. Mary, Queen of Scots did not do so because she was a Roman Catholic and the church had become Protestant by the time of her personal reign. However, she was in the building at least three times during the 1560s, when she opened parliament in the west end of the church and she once sent her husband, Lord Darnley, to attend a service. He complained afterwards that John Knox preached such a long sermon that he missed his dinner.
After Mary’s forced abdication, Scotland was placed under the government of her illegitimate half-brother, James Stewart, Earl of Moray. The Regent Moray had been one of the Lords of the Congregation, and was a staunch friend of John Knox. After Moray was assassinated in Linlithgow in 1570, he was buried in St Giles’, and John Knox preached at his funeral. Moray’s monument was destroyed during later alterations, but its original brass plate survived and was fitted to his replica memorial in the Holy Blood Aisle, which also has a stained glass window depicting his death and funeral.
Mary’s son, King James VI, regularly attended services in the Reformed St Giles’, often interrupting the sermon to argue with the Minister over points of theology until in 1603 James inherited the throne of England too and moved to London.