Lionel presented himself again in the House, declared his objection to the oath and withdrew. A vote on the new principle was taken immediately and was passed with little opposition. Lionel was summoned back in. He entered the Chamber flanked by Abel Smith and Lord John Russell, who had supported and encouraged him throughout his campaign. An eleven-year struggle thus ended with a simple ritual that nevertheless represented a major step forward in the long campaign for religious freedom and Jewish assimilation.
Lionel remained MP for the City of London for sixteen years. The year after he took his seat, he was joined in the Commons by his brother, Mayer, who was elected MP for Hythe in Kent. In 1865 his son Nathaniel became MP for Aylesbury in Buckinghamshire where the Rothschild family owned a number of properties.