Don Pedro’s rebuilding of the city went on for years. Old city walls were expanded and an entirely new wall was built along the sea front. Fortresses along those walls and further up and down the coast from the city were modernized, and the Arsenale—the naval shipyards—were expanded considerably. Don Pedro also built the viceregal palace as well as a dozen blocks of barracks nearby, a square grid of streets lined with multi-storied buildings—unique in Europe for its time. Today, that section of Naples is still called the “Spanish Quarter”. The goal was to make not just the city of Naples, but the Gulf of Naples and eventually, the entire vice-realm invulnerable—that is, the entire southern Italian peninsula.