Historically, Buenos Aires has been Argentina's main venue of liberal, free-trading, and foreign ideas. In contrast, many of the provinces, especially those to the city's northwest, advocated a more nationalistic and Catholic approach to political and social issues. In fact, 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 said "May Revolution", Buenos Aires sent a number of military envoys to the provinces with the intention of obtaining their approval. Instead, the enterprise fueled tensions between the capital and the provinces; many of these missions ended in violent clashes.