Boulevard Saint-Laurent is the oldest artery leading north from the old fortifications and the most important north-south axis in Montréal's history. Initially established within the city walls in 1672 as Saint-Lambert Street, this wide thoroughfare passed through Saint Laurent gate to run as a footpath a short distance beyond the walled town into Montréal's countryside. It was extended northwest to the new parish of Saint-Laurent (established 1720), and around 1740, was extended northeast to the parish of La Visitation de Sault-au-Récollet, on the north shore of the island. Dividing the island in two, Boulevard Saint-Laurent was declared the dividing line between the east and west districts of Montréal in 1792. Within a few years the street became known as Saint-Laurent du Main, or simply The Main.

Montreal in 1717, according to Gaspard-Joseph Chaussegros de Léry

© Atlas historique du Canada, Volume I, Montreal, Les Presses de l'Université de Montréal, 1987, (plate 49)

A neighbourhood of artisans and skilled tradespeople, Boulevard Saint-Laurent was also, in the 19^th century, the business district and middle class area. By 1846, the built-up area on the level land northwest of the city walls effectively ended at the Sherbrooke Street escarpment; beyond were a few cottages, farms and orchards. The fires of 1852, which destroyed a large part of the city, led to the gradual relocation of the middle class to the north part of Saint-Laurent, where the lots were bigger, the surroundings more pleasant and the danger of fire lesser. While two- and three-storey buildings were built on Saint-Laurent after the great fires, the mid-century appearance of much of the street remained semi-rural.

Survey of the landscape of Plateau Mont-Royal, circa 1860

© Drawing by Simon Péloquin, Continuité, No. 66, Fall 1995, p.17

View of Boulevard Saint-Laurent, from the northwest corner of Pine Avenue, circa 1932

© City of Montreal Records and archives management

Montréal's rapidly increasing population began to push the city well beyond its old boundaries. When horse-drawn streetcars overcame the barrier of the Sherbrooke Street escarpment in 1864, the upper reaches of Saint-Laurent came under more intensive development. As property values increased, lot frontages were reduced to twenty-five feet and buildings rose to three and sometimes four storeys. Although in 1860 it was still fashionable for middle-class families to live on Boulevard Saint-Laurent between Saint-Antoine and Sherbrooke, where their favourite businesses and their own business holdings were located, there was a gradual separation between their place of residence and place of work. Most Anglophones started settling in the west in what is called today the Golden Square Mile, and Francophones in the east, in the Quartier Latin.