ownership through a rational appeal to the social function of property. Despite the efforts of these groups, land ownership continued to concentrate, and both at the time of MST's founding and in the present day Brazil has had a highly dynamic and robust agricultural business sector that came, say some, at the price of extensive dislocation of the rural poor. MST questioned the scope of the benefits from the alleged efficiency of the change, given that since 1850 Brazilian land development had been concerned with the interests of a single class – the rural bourgeoisie. While the MST frames its policies in socio-economic terms, it still points to Canudos and its alleged millenarism to legitimize its existence and to develop a powerful mystique of its own. A great deal of the early organizing in the MST came from Catholic communities. Much of MST ideology and practice come from a social doctrine of the Catholic Church: that private property should serve a social function. This principle developed during the 19th century and became Catholic doctrine with Pope Leo XIII's Rerum novarum encyclical, promulgated on the eve of the 1964 military coup. This doctrine was evoked by President João Goulart at a rally in Rio de Janeiro, at which he offered a blueprint for political and social reforms and proposed expropriation of estates larger than 600 hectares in areas near federal facilities such as roads, railroads, reservoirs and sanitation works; these ideas triggered a strong conservative backlash and led to Goulart's loss of power. Nevertheless, the Brazilian Catholic hierarchy formally acknowledged the principle in 1980. In Brazilian constitutional history, land reform – understood in terms of public management of natural resources – was first explicitly mentioned as a guiding principle of government in the 1967 constitution, which sought to institutionalize an authoritarian consensus after the 1964 coup. The military dictatorship intended to use land reform policy to develop a buffer of conservative small farmers between latifundia owners and the rural proletariat. In 1969, at the most repressive point of the dictatorship, the 1967 constitution was amended by a decree (ato institucional) by a junta that held interim power during the final illness of president Arthur da Costa e Silva, authorizing government compensation for property expropriated for land reform. This compensation would be made in government bonds rather than cash, previously the only legal practice (Art. 157, §1, as amended by Institutional Act