Grand Ma[i]gne ("Great Maina", in Greek: Μεγάλη Μαΐνη) or Vieux Ma[i]gne ("Old Maina", in Greek: Παλαιά Μαΐνη) was a Frankish castle in the Mani Peninsula, Greece. It was built, according to the Chronicle of the Morea, ca. 1248–1250 AD by William II Villehardouin, the Prince of Achaea. He was captured by the Byzantines in 1259 at the Battle of Pelagonia, and had to give up the castle as part of his ransom.
The location of the castle hasn't been determined. Modern usage refers to the castle of Porto Kagio as "Mani", but medieval portolans place the castle on the western shore of the peninsula. One candidate is the settlement of Tigani, but although a sizeable medieval town it shows no traces of having been the site of a Crusader fortress; however, the nearby site of Cavo Grosso (Cape Thyrides) shows traces of fortifications and occupies a commanding position.
- Bon, Antoine (1969). La Morée franque. Recherches historiques, topographiques et archéologiques sur la principauté d’Achaïe (in French). Paris: De Boccard. pp. 502–504.