In 1502, the Venetians changed the fortifications on the southwest side into an independent rampart and erected an artificial mound of boulders to which they attached a chain.

After the Treaty of Karlowitz (1699), the Venetians erected a sturdy tower and bastions with cannons on the islet, thus creating the well-known fortress that dominates the entrance to the port of Nafplio today.

By order of the newly arrived King George I, the castle was disarmed in 1865 and became the residence of the city's executioner and the location of for executing prisoners via guillotine.

Finally, with the creation of the Greek National Tourism Organisation, the castle was restored in the 1930s,[3] and was transformed into one of the first tourist centers in Greece.

The castle then housed a hotel with 12 rooms and a restaurant that was mentioned in contemporary international travel guides.