CYCLE of Indiction, a period of 15 years, in use among the Romans. It has no connection with the celestial motion, but was instituted, according to Baronius, by Constantine; who having reduced the time which the Romans were obliged to serve to 15 years, he was consequently obliged every 15 years to impose, or indicere according to the Latin expression, an extraordinary tax for the payment of those who were discharged; and hence arose this cycle, which, from the Latin word indicere, was styled indiction.