Who united Norway, Denmark and, Sweden?

Margaret I, (born 1353, Soborg, Den.—died Oct. 28, 1412, Flensburg), regent of Denmark (from 1375), of Norway (from 1380), and of Sweden (from 1389), who, by diplomacy and war, pursued dynastic policies that led to the Kalmar Union (1397), which united Denmark, Norway, and Sweden until 1523 and Denmark and Norway until 1814.