genius

In Roman mythology, the spirit personifying the male capacity of a family (gens) to reproduce itself, residing exclusively in the male head of the family. The corresponding female capacity was the iuno.

Later, the genius was transformed into the man's higher self and as such was worshipped by him, especially on his birthday. A popular cult of the emperor's genius developed as early as the reign of Augustus. Other developments were the genii of places, buildings, and corporations.