The castle looks down over Teguise from nearby. It provides exceptional views of almost the whole island as it is built on the summit of the Guanapay volcano. The first Normans may have built a look-out tower here in the fourteenth century (1386), around which Sancho Herrera, the first sole governor of the island, built a fortress. This was attacked by pirates and had to be rebuilt in 1588 by Leonardo Torriani, Philip II's architect.

At the end of the eighteenth century a cistern was dug in the crater of the volcano to collect water. In the early years of this century it was a military dovecote. The damage done by the passing of time was rectified in restoration work in 1977 and more recently in 1989.

Nowadays it houses the Museo del Emigrante (Museum of the Emigrant) and inside there is a collection of illustrated documents (historic deeds, ships charts, contracts, photographs and so on) as well as written documents and goods belonging to Canarian emigrants. The document that confirms that people from Teguise, faced with the damage caused by the eruptions of 1730, founded the city of San Antonio, Texas in the USA is in the museum.