The first Congress of Visegrád was a 1335 summit in Visegrád in which Czech king John I of Bohemia, Charles I of Hungary and Casimir III of Poland formed an anti-Habsburg alliance. The three leaders agreed to create new commercial routes to bypass the staple port Vienna and obtain easier access to other European markets.
The congress also recognized the Czech sovereignty over the Duchy of Silesia, which the Czech kings had controlled, holding formally / de iure also the Crown of Poland. In exchange for the recognition, the Czech king John I of Bohemia gave up the Polish crown to Casimir III and received 20,000 Prague groschen. The Duchy of Silesia thus became part of the Czech Crown until 1742, when a majority of it was lost to Prussia. This majority then became part of Poland after World War II in 1945 while a minor part still belongs to the Czech Republic.
A second meeting took place in 1339, where the new king of Poland was decided upon.