Provinces of Belgium
Most of the provinces take their name from earlier duchies and counties of similar location, while their territory is mostly based on the departments installed during French annexation. At the time of the creation of Belgium in 1830, only nine provinces existed, including the province of Brabant, which held the city of Brussels. In 1995, Brabant was split into three areas: Flemish Brabant, which became a part of the region of Flanders; Walloon Brabant, which became part of the region of Wallonia; and the Brussels-Capital Region, which became a third region. These divisions reflected political tensions between the French-speaking Walloons and the Dutch-speaking Flemish; the Brussels-Capital Region is officially bilingual.
Postal codes in Belgium
Postal codes in Belgium are numeric and consist of 4 numbers. The first digit indicates the province (except for the 3xxx numbers that are shared by the eastern part of Flemish Brabant and Limburg, the 6xxx that are shared between the Hainaut and Luxembourg province, and the 1xxx that are shared by the Brussels Capital Region, the western part of Flemish Brabant and Walloon Brabant). The more zeros though the higher the number of inhabitants of that city in the province. For example: Brugge is the capital and largest urban centre of the coastal province of West Flanders so it gets the 8000 code, the second city is Kortrijk and gets 8500. 
When writing the address, the postal code is put in front of the town name.