His matricide (killing his own mother) made the young man unhappy. He could neither eat nor sleep for many days and nights. Some senior monks suggested that he should build a rice-box-shape stupa as a monument to remind people of his freat sin. The young man entered monkhood all his life. The stupa he built was called
"Phra That Kong Khao Noi Kha Mae." but today for a better feeling and for tourism it is called "Phra That Kong Khao Noi