Why did Luxembourg join the Prussian-led Zollverein customs union?

Luxembourg did not join the Prussian-led Zollverein by choice; rather, the customs union was negotiated for the grand duchy by William I of the Netherlands and subsequently ratified by his successor, William II, in 1842 against the country's own will.12

Despite this initial lack of consent, Luxembourg soon recognized the economic benefits of the arrangement. Membership in the union facilitated the country's transformation from an agricultural society into an industrial one, supported by improvements to its road network and the development of its railway infrastructure.12