One of the theories is the consideration of Easter story of crucifixion and resurrection as a symbol of rebirth and renewal, like the cycle of the seasons – the death and return of the sun.
According to some scholars, such as Dr. Tony Nugent from Seattle University, the Easter story comes from Sumerian legend of Damuzi (Tammuz) and his wife Inanna (Ishtar), an epic myth called “The Descent of Inanna” found inscribed on cuneiform clay tablets dating back to 2100 BC. After the death of her husband, Ishtar follows him to the underworld. She enters through seven gates and her worldly attire is removed. She is judged, killed and then hung naked on a stake. After the three days Inanna and Damuzi are being resurrected and given a power to return to the Earth as the light of the sun for six months. After the six months are up, Tammuz returns to the underworld of the dead, remaining there for another six months, and Ishtar pursues him, prompting the water god to rescue them both. Thus were the cycles of winter death and spring life.
The story of Inanna and Damuzi is just one of a number of accounts of dying and rising gods that represent the cycle of the seasons and the stars. For example, the resurrection of Egyptian Horus; the story of Mithras, who was worshipped at Springtime; and the tale of Dionysus, resurrected by his grandmother.