May 21, 1917

Dennis Day, of Irish parents, is born in New York, NY

May 21, 1650

James Graham, (Montrose), Scottish royalist commander, executed by Cromwellian government

James Graham, 1st Marquess of Montrose (1612 - 21 May 1650), was a Scottish nobleman and soldier, who initially joined the Covenanters in the Wars of the Three Kingdoms, but subsequently supported King Charles I as the English Civil War developed. From 1644 to 1650 he fought a Scottish Civil War on behalf of the King.

May 21, 1745

Count Daniel O'Connell, a soldier in French and British services, is born in Derrynane, Co. Kerry

May 21, 1639

Lord Deputy Thomas Wentworth imposes the Black Oath of loyalty to Charles I on all Ulster Scots over the age of 16

In 1639, Thomas Wentworth, 1st Earl of Strafford, who was the Lord Deputy of Ireland under King Charles I, imposed what became known as the “Black Oath” on the Ulster Scots population in Ireland. This controversial measure was part of Wentworth’s efforts to ensure loyalty to the Crown during a period of increasing tension between Charles I and his subjects, particularly in Scotland.