The island in its current shape was formed in the Middle Ages from a sandy area called De Schelling in the west and the original island Wexalia in the east. The name Wexalia, Wuxalia, or Wecsile is the medieval name of eastern Terschelling. However this name disappeared at the end of the Middle Ages. The last appearance of the name Wexalia is in a treaty between Folkerus Reijner Popma, then ruler of Terschelling, with king Edward IV of England in 1482.
The oldest traces of civilisation on Terschelling date from around 850, when a small wooden church was built on a hill near Seerip or Strip. This hill was later used as a burial ground and is known as the ”Striperkerkhof”.
Historically tensions existed between the inhabitants of West-Terschelling, with its strong orientation towards the sea, and the more agriculturally oriented inhabitants of East-Terschelling. In 1612 this led to the division of the island in independent political entities, West-Terschelling and East-Terschelling. Only after the French occupation at the start of the 19th century was Terschelling united as one entity again.
The Dutch navigator Willem Barentsz was born on Terschelling around 1550.
In 1666 West-Terschelling was ransacked by the English. The English fleet originally planned to attack the Dutch merchant fleet which was moored before the coast of Vlieland, the next island to the west. When the Dutch vessels retreated towards Terschelling, the English followed, destroyed 150 Dutch vessels, and landed in the harbour of West-Terschelling. The town was burnt to the ground by the English on this occasion which would become known as "Holmes's Bonfire" after the English admiral Holmes, the Great Fire of London in the very same year was considered by some to have been God's retribution. The next year, in 1667, the Dutch under command of De Ruyter executed a retaliatory expedition, and dealt the English navy a heavy blow at the Raid on the Medway (also known as the
