Page "Ambrosians" Paragraph 5
The first of these groups was formed in a wood outside Milan by three noble Milanese, Alexander Grivelli, Antonio Petrasancta, and Albert Besuzzi, who were joined by others, including some priests.
As a canonically recognized order they took the name " Fratres Sancti Ambrosii ad Nemus " and adopted a habit consisting of a brown tunic, scapular, and hood.
The brethren elected a superior with the title of prior who was then instituted by the Archbishop of Milan.
The priests of the congregation undertook preaching and other tasks of the ministry but were not allowed to accept charge parishes.
In 1441 Pope Eugene IV merged them into one congregation called " Congregatio Sancti Ambrosii ad Nemus ", made the original house the main seat, and laid down a system of government whereby a general chapter met every three years, elected the priors who stayed in office till the next chapter.