From a political point of view, the family became the most powerful of Castile, displaying the dignity of Admirals of Castile for nearly 200 years and earning the Duchy of Medina de Rioseco. They were part of the elite aristocratic power in Castile during the Middle Ages and, along with 19 other Spanish lineages, were recognized by Charles V in 1520 as one of the first Grandees of Spain. Titles held by members of the house also include “Señor de Haro” and “Masters of the Order of Santiago.”
Jurisdictionally, they guarded the manors of Mansilla, Medina de Rioseco, Melgar, Palenzuela, Peñafiel, Rueda, Torrelobatón and Tarifa.