Which king of England had a mother and a son who were both beheaded?

James VI and I (James Charles Stuart; 19 June 1566 – 27 March 1625) was King of Scotland as James VI from 24 July 1567 and King of England and Ireland as James I from the union of the Scottish and English crowns on 24 March 1603 until his death in 1625. The kingdoms of Scotland and England were individual sovereign states, with their own parliaments, judiciaries, and laws, though both were ruled by James in personal union.

James mother was Mary, Queen of Scots (8 December 1542 – 8 February 1587), also known as Mary Stuart or Mary I, reigned over Scotland from 14 December 1542 to 24 July 1567. Mary, the only surviving legitimate child of King James V, was six days old when her father died and she acceded to the throne. Mary was found guilty of plotting to assassinate Elizabeth in 1586. She was beheaded the following year at Fotheringhay Castle.

James son became Charles I (19 November 1600 – 30 January 1649), he was monarch of the three kingdoms England, Scotland, and Ireland from 27 March 1625 until his execution in 1649. Charles was accused of treason against England by using his power to pursue his personal interest rather than the good of the country. He was beheaded on Tuesday, 30 January 1649.