Constable of Castile
Constable of Castile (Spanish: Condestable de Castilla) was a title created by John I, King of Castile in 1382, to substitute the title Alférez Mayor del Reino. The constable was the second person in power in the kingdom, after the King, and his responsibility was to command the military in the absence of the ruler.
In 1473 Henry IV of Castile made the title hereditary for the Velasco family and the Dukes of Frías. After these changes, the title ceased to have any military or administrative connotations, and was simply an honorific title.