Origins of Surangama Mantra

The Surangama Mantra, also known as the White Umbrella Dharani, is the sacred mantra mentioned in the Surangama Sutra. It has 427 phrases, the last eight of which constitute the Heart Mantra. According to the Surangama Sutra, the Surangama Mantra was chanted by the Buddha to save Ananda. It was long a part of the morning incantations performed in the rural monasteries of China. *Reference

As I know, this mantra originated to save Ananda (Buddha's most trusted disciple). The story began, as Ananda was traveling through India alone (because Buddha had to attend an event somewhere else); he passed by a prostitution house. Upon passing this place, one of the prostitutes happened to be looking out the window. She fell in love with Ananda at first sight.

Knowing that Ananda is a monk, and surely wont accept her. She went to seek help from a witch, who then placed a spell upon Ananda. Though Ananda still had a clear mind, that spell made Ananda lost control of his body which brought him to that prostitute. It made him suffered, as he knew that what he was doing was against his precepts as a monk; just that his body was controlled by the witch's spell.

At this moment, Buddha who is far from Ananda felt Ananda's sufferings. The Awaken One then assigned Manjusri Bodhisattva, to aid Ananda by delivering the Surangama Mantra to him. As Ananda started to practice this mantra, the witch's spell weaken each day, and finally Ananda was freed from the grip of that prostitute.

In turn, that prostitute was convinced by Buddha and repent for her sins (at later stage she too became Buddha's disciple). As the teachings go on, it's was later brought into China and now worldwide.

Sadu, Sadu, Sadu.