In 1780 the Spanish established two combination missions and pueblos at the Yuma Crossing of the Colorado River: Mission San Pedro y San Pablo de Bicuñer and Mission Puerto de Purísima Concepción. July 1781 the Yuma (Quechan) Indians, in a dispute with the Spanish destroyed both missions and pueblos—killing 103 soldiers, colonists and Franciscan friars and capturing about 80—mostly women and children. Despite four expeditions to reassert Spanish control the Yuma Crossing remained under the Quechans' control for the next 40 years—the easiest land route to California was closed. This restriction caused most settler traffic and supplies to Alta California to come on a 30- to 60-day sailing ship journey form New Spain's towns on the Pacific Ocean. Because there were only a few settlers and they had essentially nothing to export or trade so there were only a few ships that came to Alta California. Combined with the Spanish restriction that prohibited non-Spanish shipping the average number of ships going to Alta California from 1770 to 1821 was 2.5 ship/year with 13 years showing no recorded ships.