In 1719 the first recorded Comanche raids for horses in New Mexico occurred. A Spanish military expedition was sent to retaliate, and travelled as far north as the Arkansas River (Pueblo, Colorado), but found only abandoned campsites. Meanwhile, the advance of the Comanches had destabilized the entire region, and the Apache retreat southward had become a major problem for the Spanish. Groups of refugee Plains Apache (Lipan and Mescalero) concentrated in southern Texas and New Mexico and began to attack the nearby Spanish settlements.