In Spain, Lamport came to the attention of the Marquis of Mancera, perhaps via Mancera's sister whose late husband had been posted to London and apparently knew Lamport's tutor there. In 1633 he joined one of three Spanish-sponsored Irish regiments and took part in the combat against Swedish forces in the Spanish Netherlands. His accord in the Battle of Nordlingen in 1634 attracted the interest of the Count-Duke of Olivares, chief minister to Philip IV of Spain, who eventually helped him to enter the service of the King. By that time he had hispanised his name to Guillén Lombardo (in modern Mexico generally called Guillén de Lampart).