What is the act of a human being becoming a god called?

AnswerThe act of making a mortal into a god is called deification or divinisation. In the pagan Roman Empire, a god who had once been human was called 'divus', to distinguish him from a true god ('deus'). However, the Greek language did not make this distinction, so when Latin was used in the eastern empire, the Word deus was used both for gods who had once been human and for true gods.