n unipersonal office, the Supreme Director. Formal independence from Spain was declared in 1816, in the Congress of Tucumán. Buenos Aires managed to endure the whole Spanish American wars of independence without falling again into royalist rule.
Historically, Buenos Aires has been Argentina's main venue for liberal and free-trade ideas, while many of the provinces, especially to the northwest, advocated a more conservative Catholic approach to political and social issues. Much of the internal tension in Argentina's history, starting with the centralist-federalist conflicts of the 19th century, can be traced back to these contrasting views. In the months immediately following the 25 May Revolution, Buenos Aires sent a number of military envoys to the provinces with the intention of obtaining their approval. Many of these missions ended in violent clashes, and the enterprise fueled the tensions between the capital and the provinces.
In the 19th century the city was blockaded twice by naval forces: by the French from 1838 to 1840, and later by a joint Anglo-French expedition from 1845 to 1848. Both blockades failed to force the city into submission, and the foreign powers eventually desisted from their demands.
Modern history
During most of the 19th century, the political status of the city remained a sensitive subject. It was already capital of Buenos Aires Province, and between 1853 and 1860 it was the capital of the seceded State of Buenos Aires. The issue was fought out more than once on the battlefield, until the matter was finally settled in 1880 when the city was federalized and became the seat of government, with its Mayor appointed by the President. The Casa Rosada became the seat of the President.
In addition to the wealth generated by the Buenos Aires Customs and the fertile pampas, railroad development in the second half of the 19th century increased the economic power of Buenos Aires as raw materials flowed into
