MARSIS below the southern polar ice cap, and extending horizontally about , the first known stable body of water on Mars. MARSIS MARSIS (Mars Advanced Radar for Subsurface and Ionosphere Sounding) is a low frequency, pulse-limited radar sounder and altimeter developed by the University of Rome La Sapienza and Alenia Spazio (today Thales Alenia Space Italy). The Italian MARSIS instrument is operational on the European Space Agency, "Mars Express" orbiter mission. The MARSIS Principal Investigator is Giovanni Picardi from the University of Rome "La Sapienza", Italy. It features ground-penetrating radar capabilities, which uses synthetic aperture techniques and a secondary receiving antenna
Treaty of Sapienza the Taygetus and the Parnon, were still unsubdued and held by the native Greeks, while in the northwest the Greek garrisons of the two fortresses of Argos and Nauplia continued to hold out until 1211/12. It was not until the early 1220s that the Laconian plain would come under Frankish control, and the last Greek outpost, Monemvasia, surrendered only in 1248. The treaty also preserves the names of the feudal and ecclesiastic lords of the principality who signed it as witnesses, many of which are not otherwise attested. Treaty of Sapienza The Treaty of Sapienza was concluded in June 1209