The addition of Brussels to the See's name is actually a fairly recent innovation, as part of a restructuring of the Belgian province adapting to the socio-political reality<!--at the time a 'reality' or a by one archbishop more 'desired projected reality', e.i. a 'goal'? — MEANWHILE clarify "made into was one" in the next sentence-->. Most of the secular province of Antwerp (except the 'arrondissement', i.e. district, of Mechelen itself) made into was one of several new dioceses, thus generally corresponding to the administrative structure of the country. The resulting archdiocese consisted of the province of Brabant in addition to eight municipalities in the province of Antwerp, including Bonheiden, Duffel, Mechelen and Sint-Katelijne-Waver.
This was not followed by a new break-up into dioceses, but had actually been anticipated by the creation of three vicariates general, often with their own auxiliary bishop, to accommodate the three regional entities.