During the 16th and 17th centuries, the coast of Venezuela was frequently raided by pirates. With the coastal mountains of the Central Range as a barrier, Caracas was relatively immune to such attacks, compared to other Caribbean coastal settlements, but in 1595 the Preston–Somers expedition landed and around 200 English Privateers, including George Somers and Amyas Preston, crossed the mountains through a little-used pass while the town's defenders were guarding the more frequently used one. Encountering little resistance, the invaders sacked and set fire to the town after a failed ransom negotiation. The city managed to rebuild, using wheat profits and "a lot of sacrifice". In the 1620s, farmers in Caracas discovered that Cacao beans could be sold, first selling them to native people of Mexico and quickly growing across the Caribbean. The city became important in the Viceroyalty of New Spain, as well as moving from largely native slave labor to African slaves, the first of the Spanish colonies to become part of the slave trade. The city was successful and operated on cacao and slave trade until the 1650s, when an ''alhorra'' blight, the Mexican Inquisition of many of their Portuguese traders, and increased cacao production in Guayaquil greatly affected the market. This and the destructive 1641 earthquake put the city into decline, and they likely began illegally trading with the Dutch Empire, which Caraqueños later proved sympathetic to; by the 1670s, Caracas had a trading route through Curaçao. 