• Monarch — Christian IV^[1]
• Steward of the Realm — Corfitz Ulfeldt

Undated edit

• the Domus Anatomica anatomical theatre is completed.
• the Torstenson War breaks out between Denmark–Norway and Sweden. It was resolved by the Second Treaty of Brömsebro in 1645.

Torstenson War edit

• 9 January – the Battle of Kolding begins the Torstenson War.
• 16 May – the Action of 16 May 1644.
• 1 July – the Battle of Colberger Heide.
• 13 October – the Battle of Frehmarn.
• 22 December – the Battle of Bysjön.

• 18 March – Oliger Paulli, merchant and publisher (died 1714)
• 26 March – Berte Skeel, noblewoman (died 1720)
• 21 April – Conrad von Reventlow, Grand Chancellor of Denmark (died 1708)
• 25 September – Ole Rømer, astronomer (died 1710)

• 20 February – Jens Bang, merchant (born c. 1575)
• 13 October – Pros Mund, admiral (born c. 1589)
• 18 December – Leonhard Blasius, architect (born in the Netherlands)

Date unknown edit

• October – Corfits Ulfeldt, naval officer (born c. 1600)

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  1644 altarpiece in Undløse Church.
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  1644 bust of Christian IV in Rosenborg Castle