After several failed attempts, on the first of May 1494, the commander Alonso Fernández de Lugo began the conquest of Tenerife: his military campaign would last for two years. His expedition was sponsored by the Catholic King and Queen of Castile, though he wanted to subjugate the only island that remained unconquered mainly for his own financial gain. Fernández de Lugo had just finished commanding the conquest of La Palma, in 1493, after having taken an active role in that of Gran Canaria (1483).
The Spanish Castilians landed on the coast of what is today Santa Cruz de Tenerife and soon reached agreements with some of the Guanche Menceyes (Kings). However, they did have to fight some tough battles with other natives who resisted handing over their island to the invaders. The Spanish were, in fact, defeated in the Battle of the Acentejo Ravine, after which they had to seek refuge in Gran Canaria. Finally, they returned and defeated the natives with their superior military power.
In February 1496, the island of Tenerife became part of the Kingdom of Castile. The fate of many of its inhabitants, the Guanches, was slavery, despite the fact that in 1434, Pope Eugenio IV had introduced an absolute ban on the trading of slaves from the Canary Islands. In 1511 all captive Guanches were ordered to be freed.