In the earliest writings of Hinduism, Prajapati is viewed as the ultimate creator. He is said to have made the heavens and the earth, and the creatures that live within the universe. As time went on, he became associated with various major gods, especially Brahma, Vishnu, and Shiva. Prajapati was also associated with deities that personified the major forces of the universe, especially the sun and time. In early forms, he was often depicted as a lingam figure, sitting in full lotus position, preparing to give birth to all of creation.
An early creation myth casts Prajapati as an almost unwilling participant in the role of creation. It is said that he was alone in the vastness, and to ease his loneliness, he split his self into two distinct parts: man and woman. They then procreated and from them was born the race of man. Woman eventually tired of man, however, and so she turned herself into a cow and fled. Man turned himself into a bull and followed, and again they procreated, creating the cows. She continued to tire of man and so to transform herself and flee, and man would follow and they would procreate and populate the world. In this way all the various creatures of the world were created.
Prajapati is often cast in early tales as a sacrificial character. It is said of him in the Sarapatha Brahmana that "Prajapati is sacrifice, for he created it in his own self-expression." He is intricately tied to the early belief in Hinduism that all creation was born on the back of sacrifice, and that in creating the world, Prajapati gave up a part of himself.
In the modern world, a Cult of Prajapati has sprung up that seeks to combine elements of his early worship with elements of Christianity. Prajapati in this context is said to have been a manifestation of Jesus Christ. Followers of the cult believe that his role as sacrificial lamb was the same as Christ’s.
The word Prajapati, which means Lord of Creatures, became used in later Hinduism to refer to an entire class of deities. It is said that in the time before the universe was formed, the creator Brahma created ten distinct Prajapati to assist him in creation. These can be viewed in the later cycles as distinct manifestations of Prajapati, and are given the names Atri, Angirasa, Vasishta, Bhrigu, Narada, Marichi, Pulaha, Krathu, Pulasthya, and Prachethasa.
Each of these manifestations had distinct characteristics, and appear as characters in the various holy texts of Hinduism. Atri, for example, was a famous bard. He is known best for helping to propagate the holy word Aum. Bhrigu, on the other hand, is known as a famous astrologer, and is given as the author of the astrological text the Bhrigu Samhita from around 3000 BCE.
Prajapati was also simply used later as a title for the creator god Brahma. Brahma as Prajapati Brahma embodies the creative spirit that gave birth to the infinite universes, including that in which we live.