October 20

The Spanish Duke of Alba defeats a Dutch rebel force under William the Silent.

In 1568, the Duke of Alba defeated William the Silent's rebel force, marking a key confrontation in the Eighty Years' War.

Eighty Years' War: Three thousand Spanish soldiers wade through fifteen miles of water in one night to effect the relief of Goes.

In 1572, three thousand Spanish soldiers marched through inland waterways overnight to break the siege of Goes during the Eighty Years' War.

France, Prussia, Bavaria and Saxony refuse to honour the Pragmatic Sanction, and the War of the Austrian Succession begins.

In 1740, major European powers rejected the Pragmatic Sanction, triggering the War of the Austrian Succession.

American Revolution: The Continental Association, a nonconsumption and nonimportation agreement against the British Isles and the British West Indies, is adopted by the First Continental Congress.

In 1774, the First Continental Congress adopted the Continental Association, enforcing a boycott of British goods in protest of imperial policies.

The Patent of Toleration, providing limited freedom of worship, is approved in Austria.

In 1781, Emperor Joseph II approved the Patent of Toleration, granting limited religious freedom to non-Catholic Christians in Austria.

The United States Senate ratifies the Louisiana Purchase.

In 1803, the U.S. Senate ratified the Louisiana Purchase, doubling the size of the United States.

The Convention of 1818 is signed between the United States and the United Kingdom, which settles the Canada–United States border on the 49th parallel for most of its length.

In 1818, the U.S. and U.K. signed the Convention of 1818, setting the Canada–United States border along the 49th parallel.

Greek War of Independence: In the Battle of Navarino, a combined Turkish and Egyptian fleet is defeated by British, French and Russian naval forces in the last significant battle fought with wooden sailing ships.

In 1827, British, French, and Russian fleets defeated the Ottoman-Egyptian navy at Navarino, a decisive victory in the Greek War of Independence.

Peru and Chile sign the Treaty of Ancón, by which the Tarapacá province is ceded to the latter, bringing an end to Peru's involvement in the War of the Pacific.

In 1883, Peru and Chile signed the Treaty of Ancón, ending Peru’s role in the War of the Pacific by ceding Tarapacá Province to Chile.