The rue du Midi was built in sections. The first section from the church of Saint-Nicolas to rue des Pierres dates from the city's early years. From the 12th to the 16th centuries it was called Corte Steenstraet and, after the 16th century, Melckstraet (rue du Lait) because of the proximity of milk and butter markets. The second section was laid in 1841 to link rue des Bo-gards with the train station then located at place Rouppe. It was called rue du Chemin de Fer (Spoorwegenstraat). The two were linked to become rue du Mid n 1871.
Historical Dictionary of Brussels. Paul F. State.