I operated in Italy in the early 90's when three crew (a captain and two first officers) plus two serviceable FMC's constituted a "double crew". This allowed a flight time limitation of 24 hours which could be extended by half of any time spend on the ground. There were no limitations on the number of sectors flown and my worst day involved 11 flights and a duty period of 26 hours! Absolutely crazy but totally legal at that time.