Terra Mater or Tellus Mater was a goddess personifying the Earth in Roman mythology, with both names meaning "Mother Earth" (a common metaphorical expression for the Earth and its biosphere as the giver and sustainer of life) in Latin. She was associated with Ceres in respect to growing crops, was responsible for the productivity of farmland, and was also associated with marriage, motherhood, pregnant women, and pregnant animals. Her Greek counterpart is Gaia.
During the festivities, a pregnant cow was sacrificed, the calf fetus burned and the ashes saved for the Parilia festival (an agricultural festival performed annually on April 21). The whole event was governed by the Vestal Virgins and the Pontifex Maximus.
The purpose of the sacrifice was to assure the fertility of the planted grain already growing in the womb of Mother Earth in the guise of Tellus, to whom the sacrifice was offered. As with certain other rituals over which the Vestals presided, the unborn calf is a liminal or mediating being: not yet born, but living; not a full-fledged victim, but sacrificed. The role of the Vestals emphasizes their importance in linking through the ritual reuse of elements the Earth's fertility, the health and safety of the flocks, and the security of the city, including and especially its military security against invasion.
A similar spring festival in China was witnessed in 1804 by the British ambassador to China, John Barrow. At the temple of Earth, a large porcelain cow was carried in procession then shattered to reveal several small cow-images inside. These were distributed among the people as tokens of a good growing season. Fowler speculated that the Chinese rite was in origin an animal sacrifice similar to that of the Fordicidia.