 The town of Yarmouth on the Isle of Wight may have been attacked by the French in 1543; if so, this raid probably encouraged the construction of a castle there as part of the second wave of Device Forts. The fort functioned alongside the existing defences in the Solent and protected the main crossing from the west side of the island to the mainland. Yarmouth Castle was a square artillery fort built around a central courtyard with an angular, "arrow-head" bastion protecting the landward side. It was initially equipped with three cannons and culverins, and twelve smaller guns, firing from a line of embrasures along the seaward side of the castle. It was garrisoned by a small team of soldiers, consisting of a master gunner, a porter and 17 soldiers, commanded by Richard Udall, the castle's first captain. Udall lived in the castle, but the soldiers resided in the local town.
