Paranhos, now Viscount of Rio Branco, led a cabinet from 1871 to 1875. Two serious crises arose that challenged its viability and undermined the foundations of the monarchy. The first resulted from the controversy over the Law of Free Birth, which Caxias voted for. The law was to emancipate children born to slave women after its enactment. With half of Conservative Party members supporting the bill and the other half staunchly opposed, a serious rift opened in the ranks. Opponents represented the interests of powerful coffee farmers such as Caxias, planters who had long been the main political, social, and economic supporters of the Conservative Party.