The union Eric of Pomerania was king of joined how many kingdoms under a single monarch?
Engelbrekt rebellion: The Engelbrekt rebellion was a rebellion in 1434–1436 led by Swedish nobleman Engelbrekt Engelbrektsson against Eric of Pomerania, the king of the Kalmar Union. Kalmar Union: The Kalmar Union or Union of Kalmaris (Danish, Norwegian and Swedish: "Kalmarunionen" ; Latin: "Unio Calmariensis" ) was a personal union that from 1397 to 1523 joined under a single monarch the three kingdoms of Denmark, Sweden (then including parts of Finland), and Norway, together with Norway's overseas dependencies (then including Iceland, Greenland, the Faroe Islands and the Northern Isles).
three