Around 1000 CE there were several agricultural developments (described sometimes as an agricultural revolution) that resulted in an increase in production, especially food production. The economy started to develop at a fast pace, and the higher productivity allowed workers to farm more land or to become tradesmen.

Much of the western Netherlands was barely inhabited between the end of the Roman period until around 1100 CE, when farmers from Flanders and Utrecht began purchasing the swampy land, draining it and cultivating it. This process happened quickly and the uninhabited territory was settled in a few generations. They built independent farms that were not part of villages, something unique in Europe at the time.

Guilds were established and markets developed as production exceeded local needs. Also, the introduction of currency made trading a much easier affair than it had been before. Existing towns grew and new towns sprang into existence around monasteries and castles, and a mercantile middle class began to develop in these urban areas. Commerce and town development increased as the population grew.

The Crusades were popular in the Low Countries and drew many to fight in the Holy Land. At home, there was relative peace. Viking pillaging had stopped. Both the Crusades and the relative peace at home contributed to trade and the growth in commerce.

Cities arose and flourished, especially in Flanders and Brabant. As the cities grew in wealth and power, they started to buy certain privileges for themselves from the sovereign, including city rights, the right to self-government and the right to pass laws. In practice, this meant that the wealthiest cities became quasi-independent republics in their own right. Two of the most important cities were Bruges and Antwerp (in Flanders) which would later develop into some of the most important cities and ports in Europe.