1645

Events
 January 10 – Archbishop of Canterbury William Laud executed for treason on Tower Hill, London.
 January 14 – English Civil War: Fairfax appointed Commander-in-Chief.
 January 29 – English Civil War: Armistice talks opened at Uxbridge.
 February 2 – Covenanters defeated by Montrose at the Battle of Inverlochy
 February 15 – English Civil War: New Model Army is founded officially
 February 29 – English Civil War: Uxbridge armistice talks failed.
 March 4 – English Civil War: Prince Rupert left Oxford for Bristol.
 March 31 – Fearing the spread of the plague, Edinburgh Town Council bans all gatherings except weddings and funerals
 April 3 – Lords pass Self-Denying Ordinance.
 April 10 – Because of the plague, Edinburgh town council orders that the college graduation ceremony should be brought forward so that students can leave the city (in November 19, teaching continues in Linlithgow)
 April 23 – English Civil War: 150 Irish soldiers bound for service with King Charles, were captured at sea by parliamentarians who celebrated St George's Day by joyfully killing them all at Pembroke.
 May 9 – Covenanters defeated by Montrose at the Battle of Auldearn.
 June 1 – English Civil War: Prince Rupert' army took sacked Leicester
 June 10 – English Civil War: Cromwell confirmed as Lieutenant-General of Cavalry.
 June 14 – English Civil War: Battle of Naseby – 12,000 Royalist forces are beaten by 15,000 Parliamentarian soldiers
 June 28 – English Civil War – the Royalists lose Carlisle.
 July 2: Fight at Alford, Aberdeenshire.
 July 10 – English Civil War: Cromwell won the Battle of Langport, Somerset.
 July 23 – Alexei Mikhailovich, Tsar of Russia came to the throne.
 September 10 – English Civil War: Prince Rupert surrendered Bristol.
 September 13 – Covenanters defeated Montrose at the Battle of Philiphaugh, Selkirk.
 September 24 – English Civil War: Parliamentarians defeated Royalist cavalry at the Battle of Rowton Heath.
 October 8 – English Civil War: Final crushing of Basing house begun.
 October 8: Jeanne Mance founds the Hôtel-Dieu de Montréal, the first hospital in North America.
 October 11 – English Civil War The re-fortification of Bourne, Lincolnshire castle against threatened Royalist attack, was begun.

 Siege of Raglan Castle during the English Civil War
 The Long Parliament outlaws the 1559 version of the Book of Common Prayer
 Beginning of the Maunder Minimum, a time period when sunspots became exceedingly rare
 Founding of the Stolberg-Wernigerode branch of the family of counts of Stolberg and Wernigerode in Germany
 Wallpaper begins to replace tapestries as a wall decoration
 Mechanical calculating machine invented by Blaise Pascal.