Complex sentence: From 1949, Cardinals has been Grand Masters, though the Pope remains sovereign of the order, thus enjoying the protection of the Holy See, with headquarters at Palazzo Della Rovere in Rome, close to the Vatican City.
Split into simpler sentences: From 1949, Cardinals has been Grand Masters, though the Pope remains sovereign of the order, which thus enjoys the protection of the Holy See. Its headquarters is at Palazzo Della Rovere in Rome, close to the Vatican City.