1) Cardinal 2) Driving age in old Rome 3) II to the IVth power 4) Income tax Amendment 5) Iv squared 6) IV x IV 7) Last pope gregory 8) Louis who was guillotined 9) Memorable Louis 10) Roman 16 11) Sixteen 12) Sixteen, at times 13) Square in old Rome 14) Sweet age for a Roman 15) Sweet age for Caesar 1) Sixteen