The Empire of Brazil promulgated the Ato Adicional (Additional Act), a constitutional amendment passed during the Regency period. The act significantly altered Brazil’s political structure by increasing provincial autonomy and reforming the regency system. It replaced the collective regency with the possibility of a single regent (Regência Una) to strengthen executive authority. The law also created the Município Neutro, separating the city of Rio de Janeiro from the surrounding province and placing it directly under imperial control.
