From 1563 until the death of the last teacher in 1851, there was a prebendary in the Cathedral of the Canary Islands in charge of the education of children. In fact, it could be said that this prebendary was the only continuous secondary school teacher there was in the Canary Islands until the beginning of the nineteenth century when the High School of La Laguna was founded in the island of Tenerife. This member of the cathedral chapter was called "racionero" in Spanish and his position "ración". This article will examine this interesting Chair of Grammar from its venue to the teacher's salary, the students, the teachers or the rights and duties of these teachers.