The story
Long ago the solar-dynasty king Mandhata ruled with justice, and his people lived in plenty. Yet for three years no rain fell. Crops failed, sacrifices stopped for want of grain, and the people came to the king in despair.
Mandhata searched his conscience and could find no wrong he had done. Taking a few companions, he went into the forest to seek the advice of sages, and came to the hermitage of Angiras, the son of Brahma.
Angiras listened and said: “Your suffering is not caused by any fault of yours. But there is a remedy. In the bright half of Ashadha comes the Ekadashi called Padma or Devshayani. Keep its fast with your family and your subjects, and the rains will return.”
The king returned to his capital and kept the fast as instructed, with worship, the night vigil and charity, and all his people joined him. Soon the clouds gathered and heavy rain fell. The fields turned green and the kingdom prospered again.
Because Vishnu is said to lie down to his cosmic sleep on this day, it begins Chaturmas, the four holy months in which weddings and house-warmings are traditionally postponed until he wakes on Devutthana Ekadashi.
Retold in our own words from the traditional story; versions told in families and booklets differ in details.