Frostating
Frostating was one of the four ancient popular assemblies or things of medieval Norway. Historically, it was the site of court and assembly for Trøndelag, Nordmøre, and Hålogaland. The assembly had its seat at Tinghaugen in what is now Frosta Municipality. It functioned as a judicial and legislative body, resolving disputes and establishing laws.
Frostating and Norway's three other ancient regional assemblies, the Borgarting, Eidsivating, and Gulating, were joined into a single jurisdiction during the late 13th century, when King Magnus the Lawmender had the existing body of law put into writing.
Tinghaugen
Tinghaugen, from the Old Norse words þing meaning 'assembly' and haugr meaning 'hill', is close to the medieval church at Logtun. The site is represented by the Frostatinget bautasten at Tinghaugen. Frostating was arguably Norway's oldest court, pre-dating the Viking Age. The Frostating had authority over the eight districts in Trøndelag including Norðmørafylki and Naumdølafylki and at a later time, it also included Hålogaland. When Norway was united as a kingdom, the existing lagting 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.Magnus Lagabøtes landslov
The first seeds of democratic evolution appeared in matters of law. When Norway was united as a kingdom, the four independent lagting – Frostating, Gulating, Eidsivating, and Borgarting – were the most supreme bodies of law, acting as both legislative assemblies and courts. In 1274, with the consent of all lagting, King Magnus the Lawmender promulgated a new national law, a unified code of laws for the Kingdom of Norway, which was exceptional of its time. With this, the Frostathing Law was replaced by the new law, significantly reducing the legislative power of the assembly, and centralising power in the realm.A unified code of laws for a whole country had until then only been introduced in the Kingdom of Sicily in the Liber Augustalis promulgated in 1231 by Frederick II, [Holy Roman Emperor] and the Fuero Real compiled during the reign of Alfonso X of Castile.
The law remained in force until Frederik III, king of the Denmark–Norway, promulgated absolute monarchy in 1660. This was codified in the King Act of 1665 which functioned as the Constitution of Norway of the Union of Denmark-Norway until 1814.