Charles I, the sickly second son who lost his crown and head
Charles I was so frail as a toddler that he was left behind in Scotland when his family moved to England in 1603, and he wore boots of Spanish leather and brass to strengthen weak ankles. He was never meant to reign. His clash with Parliament ended with the only execution of a reigning English monarch after a public trial.
Born at Dunfermline Palace in 1600, the second son of James VI of Scotland, he could not walk the length of the palace's great hall unaided until he was about three and a half. He stammered all his life. He adored his taller, stronger brother Henry, Prince of Wales, whose death in 1612, probably from typhoid, made the 12-year-old Charles heir. Over time he overcame his weakness, possibly caused by rickets, to become a skilled rider, marksman and fencer.
In 1623 Charles and his father's favourite, the Duke of Buckingham, travelled to Madrid in disguise to win the Spanish infanta Maria Anna. The trip was an embarrassing failure: the Spanish wanted him to convert and demanded toleration for English Catholics. Londoners cheered his bride-less return. Two years later he married the 15-year-old French princess Henrietta Maria, secretly promising her brother Louis XIII relief for Catholics while assuring Parliament he would do no such thing. She refused to attend his Protestant coronation in 1626.
Believing in the divine right of kings, Charles levied taxes without Parliament's consent and promoted high church clergy whom Puritans suspected of popery. Forcing Anglican practices on the Church of Scotland provoked the Bishops' Wars and strengthened parliaments in both kingdoms. Revived impeachment, which his father had warned he would regret encouraging, was later turned against his own ministers.
Civil war began in 1642. Defeated by the New Model Army in 1645, Charles surrendered to the Scots, who handed him to Parliament. He refused to become a constitutional monarch, escaped briefly in November 1647, and plotted with Scotland from captivity on the Isle of Wight. In January 1649 he was tried and executed for high treason, and England became a republic until his son Charles II was restored in 1660.
Source: Charles I of England