The Order of Saint Michael of the Wing originally was founded in 1147 by King D. Afonso (Henriques) I of Portugal with a group of Knights of the Order of Saint James from the Kingdom of León who assisted him in retaking Santarém from the Moors on the Feast of Saint Michael, May 8, 1147.

Originally, the order was formed from members of the Military Order of Saint James; thus, the reason why it maintains on its Coat of Arms the red sword of the Apostle whose body is venerated in Santiago de Compostela. The sword is accompanied at the blade by two fleur de lis representing the Cistercian Rule its original members observed at the Royal Monasteries of Alcobaça, Portugal and Oseira, Santiago de Compostela, Spain, and where the Order, along with six other Military Orders, was headquartered until the reestablishment of all Orders as non-military Orders of "Honorific Knighthood" in 1834.

The Order's first Statutes were approved by Pope Alexander III in 1171 and because of this fact the year 1171 is often referred to (in error) as the date of the Foundation.

The Royal Brotherhood of the Order of Saint Michael of the Wing (known in Portugal as of September 29, 2023) as the Royal Brotherhood of the Order of the Archangel Saint Michael, Angel of Portugal and of Peace is one of 13 Canonically Erected Diocesan Associations of the Faithful, created as of the year 2000 as the only active social compliment for the personal sanctification and social support of members of the Order that is 2021 celebrated its 850th Jubilee with a Holy Year proclaimed by Pope Francis.