Birthday of Avalokitesvara

The Chinese have a tradition of celebrating the Birthday of Avalokitesvara on the 19th day of the 2nd Lunar month, his Day of Enlightenment on the the 19th day of the 6th Lunar month, and his Day of Renunciation on the 19th day of the 9th Lunar month.

I suppose this is based on the ancient chinese legend of the life of Guanyin (Avalokitesavra), depicted as a certain Princess Miao Shan 妙善公主 who saved all the people of her country from calamity, and later became a Buddhist Nun, finally transforming into Guanyin herself.

This legend, originating from the Mongol Yuan Dynasty (1271-1368AD), has Guanyin reborn as the 3rd daughter of King Miao Zhuang 妙庄王.

Source

http://www.lianhuayuan.net/index41.html