The "Unitarian" Constitution of 1819 was immediately rejected by the provinces, and a state of anarchy ensued following the Battle of Cepeda. The only cause that could regain unity among the hostile factions was the 1825 invasion of what today is Uruguay on the part of Brazilian Empire. Uruguay, then known as the "Province of the Eastern Bank of the Uruguay River", was considered a somewhat breakaway Province, since Montevideo served as the seat of the Royalist Viceroy Francisco Javier de Elío during its war on the May Revolution; and that, after the independentists victory, the Province became the main stronghold of the Federal League leader José Gervasio Artigas, who waged a long and bitter dispute during the 1810s against the Unitarians about the shape the national organization would have.