The island of Gotland rests upon sedimentary rocks from the Silurian age that dip toward the southeast. These layers consist mainly of limestones and shales deposited in a shallow sea, creating karstic formations known as rauks through weathering.
Archaeological evidence confirms human occupation of the island of Gotland since approximately 7200 BCE. Sites such as the Ajvide Settlement demonstrate continuous habitation through prehistory with genetic links to modern-day Finns found in Middle Neolithic remains.
The world's largest Viking silver treasure emerged from a field at Spillings farm northwest of Slite on the 16th of July 1999. It consisted mostly of coins numbering about fourteen thousand from foreign countries with a combined weight of approximately one hundred kilograms.
Valdemar Atterdag of Denmark invaded the island of Gotland in 1361 after conflicts between German merchants and countryside peasants required intervention by King Magnus III of Sweden in 1288. The Victual Brothers occupied the island in 1394 before an invading army of Teutonic Knights conquered it in 1398.
In March 2015, the Swedish government decided to begin reestablishing a permanent military presence on the island of Gotland. The Gotland Regiment was re-established in 2018 marking the first time since World War II that a new regiment formed in Sweden.