First Battle of Acentejo The First Battle of Acentejo took place on the island of Tenerife between the Guanches and an alliance of Spaniards , other Europeans , and associated natives ( mostly from other islands ) , on May 31 , 1494 , during the Spanish conquest of this island . It resulted in a victory for the Guanches of Tenerife . The Spaniards were under the command of the Adelantado ( " military governor " ) Alonso Fernández de Lugo , who had sold his properties in order to finance his conquest of Tenerife . Fernández de Lugo was aided by the fact that missionaries had already begun to Christianize the Guanches of Tenerife , and several of the Guanches ' " menceyatos " or kingdoms , which included Guimar , Abona , Adeje , and later Anaga , were friendly to the Castilians ( and known in Spanish as " bandos de paz " ) . Fernández de Lugo landed at Añazo , near present - day Santa Cruz de Tenerife , in late April , and built the fortified camp of " el Real de Santa Cruz " . Advancing towards the interior of the island , Fernández de Lugo confirmed his friendship with the " bandos de paz " and attempted to reach the same arrangement with other Guanche " menceyatos " , including Taoro . Bencomo , the ruler of Taoro , refused Fernández de Lugo ' s terms , and instead began to form his own alliance against the Castilians , composed of the " menceyatos " of Tacoronte , Tegueste , Daute , and Icod . In a state of war , Fernández de Lugo advanced through present - day San Cristóbal de La Laguna to the area known as Acentejo . The Castilians committed the terrible blunder of walking blindly into the ravine now called Barranco de San Antonio ( " Farfan " was its Guanche name ) , in Acentejo . Despite their technological superiority — the Spaniards , protected with armour and shields , fought with blunderbuss es and cannon — the Guanches , fighting naked , attacked them from the slopes with stones and spears of hardened wood ( known as " banotes " ) . Unable to maneuver with their horses , because these slopes were covered with very thick , arboreal brush , the Guanches , who numbered some 3 , 300 men under the leadership of Bencomo and his half - brother Tinguaro , chief of the comarca of Acentejo , made use of their mobility and intimate knowledge of the terrain to gain the upper hand . While Tinguaro with 300 men ambushed the vanguard of the Castilian forces , Bencomo arrived at the battle with 3 , 000 men , attacking the rearguard of the dispersed Europeans . It is believed that four out of five Spanish soldiers fell in this battle , leaving 900 – 1 , 000 dead on the battlefield out of the initial 1 , 120 . The defeat was not total , however . Fernández de Lugo , though wounded , was able to escape with his life ( by exchanging the red cape of an Adelantado for that of a common soldier ) , and his surviving forces ( some 200 men ) were harried until he was forced to re - embark at Añazo and sail back to Gran Canaria . The Adelantado was able to return and defeat the native forces in two major battles : the Battle of Aguere and Second Battle of Acentejo , and other minor clashes , such as the Battle of Las Peñuelas . A town built on the site where the battle occurred is called La Matanza de Acentejo ( " The Slaughter of Acentejo " ) , which also contains a large mural commemorating the victory . This was the greatest defeat in the history of the Spanish Atlantic expansion , in terms of casualties suffered by Spain .