Brielle is a very old, fortified town. Its name is derived from the Celtic word brogilo (meaning "closed area" or "hunting grounds"). The oldest writings about Brielle indicate that the current location is the "new" Brielle. Den ouden Briel (Old Brill) must have been situated somewhere else on the Voorne-Putten Island. It received city rights in 1306. The city was for a long time the seat of the Count of Voorne, until this fiefdom was added to Holland in 1371. It had its own harbour and traded with the countries around the Baltic Sea. Brielle even had its own trading colony in Sweden.