False Dmitry I
He was the first , and most successful , of three "pretenders" who claimed during the Time of Troubles to be the youngest son of Ivan the Terrible , tsarevich Dmitry Ivanovich , who had supposedly escaped a 1591 assassination attempt . 
<triplet> Ivan the Terrible <subj> Dmitry Ivanovich <obj> child <triplet> Dmitry Ivanovich <subj> Ivan the Terrible <obj> father