After Belgian independence in 1830, sentiment in support of King William I of the Netherlands remained strong among members of the aristocracy and wealthy industrialists. Newspapers subsidized by the Dutch government, notably Le Lynx, published increasingly vitriolic attacks against the Belgian sovereign, labeling him a usurper. In March 1834, the government authorized the sale of horses owned by the prince of Orange. A subscription was raised to purchase the horses, which were sent to the prince. Done in secret, the transaction was made public on 2 April when Le Lynx, followed by other newspapers, began to list subscribers. After a demonstration at the Théâtre royal de la Monnaie on 5 April, groups formed in the streets and sacked an Orangist café and the printing works of Le Lynx. Townhouses of prominent Orangists were plundered. Republican agitators unfurled red flags. Burgomaster Nicolas Rouppe refused to call in the army and the civic guard refused to take up arms. Charles Rogier harangued the crowds to disperse. A total of 114 rioters were arrested, but all were later released and some French and Polish exiles were expelled. Opponents of an independent Belgium subsequently became reconciled to the new regime.
Historical Dictionary of Brussels. Paul F. State.