Born in Haddington around 1513, John Knox was originally ordained as a Roman Catholic priest, although he never had a parish appointment. He studied law instead and by 1546 had become a supporter of the Protestant reformer, George Wishart.

After being captured at St Andrews Castle by the French in 1547, he made his way to England. On Mary Tudor's succession to the English throne he fled to the Continent and in Geneva became a great admirer of John Calvin. He visited Scotland in 1556 and returned permanently in 1559.

Knox's condemnation of the Mass as practised by Queen Mary, led to several famous confrontations with the Queen herself. In 1560 he was installed as minister of St Giles, in Edinburgh, a position he held until his death in 1572.