 Many of them worked in the building of works so special as the "El Escorial" Monastery and the Cathedral of Sigüenza, and great monuments in Galicia; however they barely left their mark in Cantabria.It is known that at the beginning of the 12th century a large number of masons of Trasmiera were called to work in the construction of Avila's City Walls.From the 15th century on it is known by documents that they were working all around Castile and that they had positions of great responsibility.