In which states did the dynastic union play an important role in the 14th – 15th centuries and why?

Dynastic unions – the rule of two or more countries by one monarch or spouses. Played an important role in the following countries:
1) Poland and Lithuania. Under the terms of the Union of Kreva in 1385, the Lithuanian prince Jagiello became the king of Poland. In 1569, the countries united into the Rzeczpospolita.
2) Castile and Aragon. The marriage between Queen Isabella of Castile and León and King Ferdinand of Aragon in 1469 led to a union between the two kingdoms and, in the 16th century, to their unification into a single Spanish state.
3) Denmark, Sweden, Norway. The Kalmar Union of 1397 established a common monarch for the three countries. In the 16th century, Sweden withdrew from the union, the Danish-Norwegian union persisted until 1814.