The Treaty of Madrid was based on the principles of "Uti possidetis, ita possideatis" from Roman law (who owns by fact owns by right) and “natural boundaries”, stating respectively in the preamble: “each party must stay with what it now holds” and “the boundaries of the two Domains... are the sources and courses of the most notable rivers and mountains”, and thereby authorizing the Portuguese to retain the lands they had occupied at the expense of the Empire of Spain. The treaty also stipulated that Spain would receive the Sacramento Colony and Portugal the Misiones Orientales. These were seven independent Jesuit missions of the upper Uruguay River. The Treaty of Tordesillas was specifically abrogated.