 Although Constantine created his apparent heirs " Caesars " , following a pattern established by Diocletian , he gave his creations a hereditary character , alien to the tetrarchic system : Constantine 's Caesars were to be kept in the hope of ascending to Empire , and entirely subordinated to their Augustus , as long as he was alive . Therefore , an alternative explanation for the execution of Crispus was , perhaps , Constantine 's desire to keep a firm grip on his prospective heirs , this — and Fausta 's desire for having her sons inheriting instead of their half @-@ brother — being reason enough for killing Crispus ; the subsequent execution of Fausta , however , was probably meant as a reminder to her children that Constantine would not hesitate in " killing his own relatives when he felt this was necessary " . 
