Distribution of Monroy in Spain
Apparently Monroy began to circulate in northern Spain on a line from east to west to Galicia and that is the reason why some books of heraldry says is a Galician surname. Monroy surname continues along the historical route of the reconquest of the kingdom Leon and Castile thereafter.
Interestingly, much of the Monroy people ended up their re-location in the beautiful region named Extremadura
See more references in the book Memorial Monroyes en Extremadura (spanish only) published in Spain in 2009, during the conmemoration of the 700 anniversary of the foundation of Monroy, Spain by Fernan Perez Monroy ,April 21, 1309 during the kingdom of Fernando IV.
There are three towns in Extremadura markedly "Monroyenses":
a) Villa de Monroy founded on April 21, 1309 by Don Fernan Perez de Monroy, butler to the Queen Doña Maria, mother of Ferdinand IV. Villa de Monroy just celebrated its 700th anniversary http://www.asociacionelbezudo.com/, here in this town is the marquisate Monroy http://www.palimpalem.com/4/Demonroy/index.html, and a spectacular castle of this surname.
b) Belvís de Monroy, who has an impressive castle that is sincerly fool, the kind that impress http://www.belvis.org/, but is in a condition very regular, almost that bad. So much so that almost is considered wasteful.
c) Valverde de la Vera, related to Nuño Pérez de Monroy, and also has a medieval tower. This last town is beatiful, with a nature fit for a garden, very worth seeing.
These three villages are in the municipal shield the shield of the monroy http://www.valverdevera.com/.
The original Coat Monroy is the golden castle in the 1st and 4th quarters, although there is a variant that put the castle in the 2nd and 3rd quarters which is not correct.
And from Extremadura traveled to the New World involved in the conquest, evangelization and colonization of new Spanish Crown land, whether in Mexico (New Spain), Colombia (Cartagena), Philippines, etc.