On This Day: October 20th

Chile and Bolivia sign the Treaty of Peace and Friendship, delimiting the border between the two countries.

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.

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.

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.

The United States Senate ratifies the Louisiana Purchase.

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

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.

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

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

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