Mary Stuart became Queen of Scots at six days old, on her father James V's death in 1542, and was sent as a child to be raised at the French court, where she was brought up Catholic and married the French dauphin, briefly becoming queen consort of France as well until his early death in 1560. She returned to Scotland in 1561 to find the country transformed in her absence: the Scottish Parliament had established Protestantism as the kingdom's religion the previous year, driven substantially by the preaching of John Knox, and Mary's open Catholic worship at court, though tolerated as a personal accommodation, sat uneasily against a Reformed political and religious establishment that had already broken with Rome.
Mary's personal life supplied fuel for a reign that could not settle: her marriage to Lord Darnley, his involvement in the murder of her secretary David Rizzio, Darnley's own murder shortly afterward, and Mary's hasty marriage to the chief suspect in that murder, the Earl of Bothwell, combined to alienate much of the Scottish nobility, Protestant and Catholic alike, and led to her forced abdication in 1567 in favor of her infant son, who was raised Protestant and became James VI, later James I of England.