In 1744, the 8th Nguyen Lord, Vũ Vương Nguyễn Phúc Khoát who governed Cochinchine, believed in a oracle that the 8th generation will be back to the capital, he supposed that Cochinchine would become an independent nation, so he set the rule to change the residents’ clothing with a view to making the custom separate from Tonkin.
“…residents must use silk, only officials can use satin. Embroidered silk and dragon and phoenix patterns are forbidden. Short dress with tight collars is used as casual wear with optional size of sleeves for both men and women. The flaps must be closed from the armpit, collars should never be wide open…” (Phủ biên tạp lục - Lê Quý Đôn)
Quần chân áo chít or a set of loose pants and a five paneled tunic - “áo năm thân” then became popular in Cochinchine. The tunic included five panels, two in the back and two in the front, sewn together along the body, and one more panel was hidden underneath. Collars are upturned and buttoned to the right. The flaps were fairly loose and going down to the knees, and the waist was not nipped like it is today. Unlike the modern ao dai (with raglan sleeves), the sleeves were as a whole with the main panel.
When Emperor Gia Long unified Cochinchine and Tonkin, the conformity of customs, including clothing became necessary. However, to change the clothing of people was not simple, it was not until the legacy of Emperor Minh Mang that a lot of edicts was issued to prohibit the cross-collared 'giao lĩnh' and four-paneled 'tứ thân', replacing them with the five-paneled 'áo năm thân'.
Over times, the five paneled áo năm thân have been modernized and Westernized into various styles, before it become what we see today.
