Now the links become more interesting but less proven:
5) Schwerin is a state in North East germany, once ruled by the Duchy of Mecklenburg-Schwerin. The House of Mecklenburg links in to the royal families of the Netherlands and Sweden:
States ruled by the House of Mecklenburg
Mecklenburg (1167–1918), with:
Mecklenburg-Stargard (1348–1471)
Mecklenburg-Schwerin (1352–1918, with interruptions)
Mecklenburg-Güstrow (1621–1701)
Mecklenburg-Strelitz (1701–1918)
Werle (1235–1436)
Sweden (1364–1389)
United Baltic Duchy (November 1918)
Netherlands (1948–1980) – via Queen Juliana of the Netherlands