How did Brussels become the capital of independent Belgium in 1830?

Brussels became the capital of independent Belgium in 1830 as a direct result of its central role in the Belgian Revolution against the United Kingdom of the Netherlands.1

During the 15-year period (1815–1830) when the southern and northern provinces were reunited, Brussels had shared the status of capital with The Hague. However, growing dissatisfaction among the southern population—driven by religious, linguistic, and economic grievances—led to an uprising in August and September 1830.12

Brussels served as the primary site of this resistance against the rule of William I. Following the success of the revolution and the proclamation of independence by a provisional government, the newly elected National Congress formally adopted a constitution that designated Brussels as the capital of the new Belgian state and the permanent seat of its government.1