This is the largest of the original gates along the Aurelian Wall. In 275 AD, it was called Porta Appia because it was part of the Appian Way, the main road leading into Rome since 312 BC. It was expanded during the early 5th century. Sometime during the 15th century, the name became Porta San Sebastiano to honor the nearby Basilica of Saint Sebastian. The large central archway was added before Holy Roman Emperor Charles V visited the city in 1536. Want to learn a lot more about the Aurelian Wall history? Then this is the place to come. Inside is Museo delle Mura meaning the Museum of the Wall.