For most of the history of the Baltic League, its politics were dominated by the Kingdoms of Anglia and Northumbria. In 1390, King Erik IV of Northumbria married Victoria II of Anglia, beginning an extensive period of negotiations between the two states as a result of their two dynasties becoming one. These talks eventually expanded to include all the constituent regions of the Baltic League, and ended with the signing of the Peace of Halle in 1417.
The Peace is notable for being the document that formed the political entity now known as the Kingdom of Aloia. The Peace established a unified dynasty, the House of Uppsala, as the King of all the Balts. The Peace also established Aloia's first legislature, the High Council, consisting of one representative from each constituent region of Aloia. Aloia today has a bicameral legislature, with the upper chamber still carrying the name High Council.
Later, the Baltic League took a new name for their nation in 1593 at the Uppsala Synod. The League became Aloia, a name derived from Aloja, Mariana, the one southern Baltic city to stand up to the southern secession during the Protestant Reformation. These were the two most significant events in the transition from the Baltic League to the Kingdom of Aloia.