In Buddhist Mythology, Māyā and King Suddhodhana did not have children for twenty years into their marriage. According to legend, one full moon night, sleeping in the palace, the queen had a vivid dream. She felt herself being carried away by four devas (spirits) to Lake Anotatta in the Himalayas. After bathing her in the lake, the devas clothed her in heavenly cloths, anointed her with perfumes, and bedecked her with divine flowers. Soon after a white elephant, holding a white lotus flower in its trunk, appeared and went round her three times, entering her womb through her right side. Finally the elephant disappeared and the queen awoke, knowing she had been delivered an important message, as the elephant is a symbol of greatness.

According to Buddhist tradition, the Buddha-to-be was residing as a bodhisattva in the Tuṣita heaven, and decided to take the shape of a white elephant to be reborn on Earth for the last time. Māyā gave birth to Siddharta c. 563 BCE. The pregnancy lasted ten lunar months. Following custom, the Queen returned to her own home for the birth. On the way, she stepped down from her palanquin to have a walk under the Sal tree (Shorea robusta), often confused with the Ashoka tree (Saraca asoca), in the beautiful flower garden of Lumbini Park, Lumbini Zone, Nepal. Maya Devi was delighted by the park and gave birth standing while holding onto a sal branch. Legend has it that Prince Siddhārtha emerged from her right side. It was the eighth day of April. Some accounts say she gave him his first bath in the Puskarini pond in Lumbini Zone. But legend has it that devas caused it to rain to wash the newborn baby. He was later named Siddhārtha, “He who has accomplished goal”.

Source: Wikipedia