A small fortalice was built in 1388 under the direction of John Hawley. The present Guntower building is the earliest surviving English coastal fortress specifically built to carry guns. It was built by the corporation of Dartmouth between 1481 and 1495 and additions, including open-air gun platforms, were made during the 16th century by Henry VIII and again in the 17th century in order to accommodate new military technology.

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