 His "Portrait of Juan Lopez Gallo and His Three Sons", dating back to 1568, reflects both his artistic style and the strength of his ties to the Spanish upper class.There, Pourbus dealt with his clients' differing customs by adjusting the size of his retables to suit the size of altar that was customary in Spain at the time.Sometimes, he left the actual execution of paintings for his more distant clients to atelier staff, as shown in his "Mount at Calvary" in the Cathedral of San Pedro of Soria.