1645 in Denmark

Incumbents

• Monarch — Christian [IV of Denmark|Christian IV]
• Steward of the Realm — Corfitz Ulfeldt

Events

• 3 March — Simon Paulli gives his first public lecture in the new Domus Anatomica in Copenhagen.
• 25 May sinks near Buskär outside the harbour of Gothenburg.
• 13 August — The Second Treaty of Brömsebro is signed, putting an end to the Torstenson War. The island Øsel is ceded to Sweden.

Undated

• Stephanius publishes Saxonis Grammatici Historiæ Danicæ Libri XVI, a Latin edition of Saxo Grammaticus's Gesta Danorum.

Culture

Art

• Abraham Wuchters creates a full-length portrait of Ulrik Christian Gyldenløve.

Deaths

• January 31 — Hans Ulrik Gyldenløve, diplomat, illegitimate son of Christian IV