"Then at last Avalokiteshvara arrived at the summit of Marpori, the 'Red Hill', in Lhasa. Gazing out, he perceived that the lake on Otang, the 'Plain of Milk', resembled the Hell of Ceaseless Torment. Myriad beings were undergoing the agonies of boiling, burning, hunger, thirst, yet they never perished, sending forth hideous cries of anguish all the while. When Avalokiteshvara saw this, tears sprang to his eyes. A teardrop from his right eye fell to the plain and became the reverend Bhrikuti, who declared: 'Child of your lineage! As you are striving for the sake of sentient beings in the Land of Snows, intercede in their suffering, and I shall be your companion in this endeavour!' Bhrikuti was then reabsorbed into Avalokiteshvara's right eye, and was reborn in a later life as the Nepalese princess Tritsun. A teardrop from his left eye fell upon the plain and became the reverend Tara. She also declared, 'Child of your lineage! As you are striving for the sake of sentient beings in the Land of Snows, intercede in their suffering, and I shall be your companion in this endeavor!' Tārā was then reabsorbed into Avalokiteshvara's left eye."
Tara (Buddhism)

January 1, 1970