When Norway was united as a kingdom (900 - 1030 AD), the first lagtings were constituted as superior regional assemblies, Frostating being one of them. These were representative assemblies at which delegates from the various districts in each region met to award legal judgments and pass laws.

The first germs of democratic evolution appeared in matters of law. The ancient regional assemblies - Frostating, Gulating and Eidsivating - were eventually joined into a single jurisdiction, and King Magnus Lagabøte had the existing body of law put into writing (1263 - 1280). This compilation of codified law which applied throughout the realm was exceptional for its time, and remained in force until Frederik III, king of the Danish-Norwegian union, promulgated absolute monarchy in 1660. This was codified in the King Act of 1665 which functioned as the constitution of the Union of Denmark-Norway until 1814.