As the previous reviewer says: Starz are a joke, they're given priceless 80 rating shows to work with and just cancel them like it's nothing. Apple are also following this sad pathetic trend by cancelling Shantaram, worst by far though for premature cancelations was the british show utopia, and the nerve to then go and make a US version after cancelling the british version unfinished.
Can't really add anything to the previous review other than to say that Da Vincis demons is of the same calibre as Marco Polo and the recent Shogun reboot.
Just imagine the uproar if Breaking Bad was canceled on season 3.