Throughout the middle ages it was the scene of vigorous struggles between Sla y s, Byzantines, Franks, Turks and Venetians, the chief memorials of which are the ruined strongholds of Mistra near Sparta, Gerald (anc. Geronthrae) and Monemvasia, "the Gibraltar of Greece," on the east coast, and Passava near Gythium.
In the Morea, meanwhile, a few Mussulman fortresses still held out: Coron, Modon, Navarino, Patras, Nauplia, Monemvasia, Tripolitsa.
In 1263 and 1264 respectively, Michael, with the help of Urban IV., concluded peace with Villehardouin, prince of Achaia, and Michael, despot of Epirus, who had previously been incited by the pope to attack him, but had been decisively beaten at Pelagonia in Thessaly (1259); Villehardouin was obliged to cede Mistra, Monemvasia and Maina in the Morea.
In 1904 the British School at Athens began a thorough exploration of Laconia, and in the following year excavations were made at Thalamae, Geronthrae, and Angelona near Monemvasia, while several medieval fortresses were surveyed.