During the regency, Frederick instituted widespread liberal reforms with the assistance of Chief Minister Andreas Peter Bernstorff, including the abolition of serfdom in 1788. Crises encountered during his reign include disagreement with the British over neutral shipping. This resulted in two British attacks on Copenhagen, the Battle of Copenhagen of 1801 and the Battle of Copenhagen of 1807. The conflict continued in the Gunboat War between Denmark-Norway and the United Kingdom, which lasted until the Treaty of Kiel in 1814.