It 'a building consisting of two brick towers connected by an arch under which passed the Via Appia and it was the customs point between the Kingdom of Naples and the Papal States. In 1400, Portella was impregnable, and for its location was witness to history. On June 19, 1738, the fifteen-year daughter of the king of Poland, Amalia Valburga met with her betrothed, Conrad III of Naples. On May 2, 1768 Maria Amalia Carolina, Archduchess of Austria, who was married to Charles III received the honours. In 1849 Emperor Francis I of Austria was greeted.