Brazil's development as a nation has been essentially evolutionary with few sharp breaks or drastic discontinuities. The chain of events begins in 1500 when maritime-oriented Portugal, then a leading European nation engaged in a spirited rivalry with Spain in transoceanic discovery and colonization, dispatched Pedro Alvares Cabrai to reach Asia by sailing west. The eighteenth century was crucial tor defining Brazil's borders with surrounding Spanish domains—generally by force, on occasion smoothed by diplomacy. Efforts by Lisbon to tighten its hold over Brazil resulted in Pedro's dramatic cry of "Independence or death!" on September 7, 1822—commemorated as Brazil's Independence Day. The country had managed to hold together under the regency; it would be consolidated during the early years of Pedro II's long reign, Caxias's role in maintaining internal security for the empire had only begun with the success in Maranhao.