As soon as he was named provisional executive General Urquiza adopted measures looking to the adoption of a constitution. The governors of the various provinces met and it was agreed to call a Congress in which each province should have an equal vote. Buenos Aires alone protested, and to avoid the predominance of that province the session was called to meet in Santa Fé. The legislature of Buenos Aires refused to assent to this arrangement. The city rose in revolt and sent an army to attack Santa Fé, while the Congress was holding its sessions. By this action Buenos Aires practically declared her independence of the other provinces, but never asked recognition of foreign governments as an independent state. Although the rest of the confederation never took any steps to force a union, they knew that it would never do to permit Buenos Aires to remain independent with its control of the La Plata and its tributaries, which furnished the only natural communication with the interior. It was the pacific policy of Urquiza alone that prevented more serious trouble at this time. He refused to become another Rosas. On the 1st of May, 1853, a constitution was adopted which was substantially copied after that of the United States, and this constitution, with few amendments, remains the fundamental law of Argentina to-day. The Paraná River was declared free to all the world, and the city of Paraná was selected as the temporary capital, with the city of Buenos Aires as permanent capital when that province should join the union. General José Justo Urquiza was elected the first constitutional president. Under his rule the provinces greatly prospered. The connection of some of the border provinces was very slight at first, but they gradually began to see the benefits of a closer union. The relations between Buenos Aires and the confederation became so strained in 1859 that the former marched an army against Urquiza. The President defeated them and, advancing upon the metropolis, compelled them to accept the constitution and join the confederation. This was about the last national service of President Urquiza, as his term expired in 1860. For many years after that he remained governor of Entre Rios, and his influence was paramount in that section between the Paraná and Uruguay Rivers. During a revolt against his authority in 1870, the aged general and ex-President was cruelly assassinated in his own house by some followers of the opposing leader.