Why Gibraltar was valuable before Britain held it

What strategic significance did Gibraltar have before Britain captured it?

It was a fortified crossing point between Spain and Morocco, and its later Anglo-Dutch capture gave Britain a durable foothold at the entrance to the Mediterranean.

Gibraltar mattered before British possession because it guarded a crossing between Spain and Morocco at the western entrance to the Mediterranean. Moorish rulers fortified the position, and Spanish control built on that earlier military value. Anglo-Dutch forces then captured the Rock during the War of the Spanish Succession, while the peace kept the French and Spanish crowns legally separate. Spain's later siege was therefore an attempt to reverse a settlement that had changed both regional access and the European balance of power.