Constantine successfully balanced his own role as an instrument of the pax deorum with the power of the Christian priesthoods in determining what was (in traditional Roman terms) auspicious - or in Christian terms, what was orthodox. The edict of Milan (313) redefined Imperial ideology as one of mutual toleration. Constantine had triumphed under the signum (sign) of the Christ: Christianity was therefore officially embraced along with traditional religions and from his new Eastern capital, Constantine could be seen to embody both Christian and Hellenic religious interests. He may have officially ended – or attempted to end – blood sacrifices to the genius of living emperors but his Imperial iconography and court ceremonial outstripped Diocletian's in their supra-human elevation of the Imperial hierarch. His later direct intervention in Church affairs proved a political masterstroke. Constantine united the empire as an absolute head of state, and on his death, he was honored as a Christian, Imperial, and "divus".
Is there an answer to this question (If it cannot be answered, say "unanswerable"): As what type of ruler did Constantine unite the empire and church?
absolute head of state