Miranda was a gentleman from Chihuahua who had come to New Mexico on business and stayed; later he was appointed to several government positions including Governor Armijo's departmental secretary.

The governor supported the grant thinking that Mexican settlers would fend off the encroaching foreigners from the United States, as well as the hostile Indians. Two years later, another consideration was possibly revealed when Miranda and Beaubien conveyed a quarter interest in the grant to Governor Armijo. Another quarter was deeded to Taos merchant Charles Bent, in return for his promise to work on developing the grant. Whatever the reasons might have been, it took Armijo only three days after having received the grant application to approve it. In 1843, after Armijo received his quarter interest, he approved an additional adjacent grant to Beaubien's son, Narciso, and son-in-law, Stephen Louis Lee.

Then along came Charles Lucien B. Maxwell, a fur trapper from Illinois, who was working as a guide in the area. His work often brought him to the Beaubien-Miranda ranch, where he met and married one of Beaubien's six daughters - Luz who was only 15 at the time. After his marriage, Maxwell continued to lead a nomadic existence as a guide and along with Kit Carson, led Colonel John C. Fremont across the desert to California in 1846.

Fremont reported in his journal that Maxwell saved the expedition when he bravely confronted a band of some 300 Arapaho warriors just as the shooting was about to start. "You're a fool, God damn you!" Maxwell yelled at one of the attackers. "Don't you know me?" It turned out the Indians were from a village where Maxwell had lived and traded a couple of years before. Instead of fighting the two sides shook hands. Maxwell knew the land and its fierce people and the task courage and self-confidence.
 

In the same year, General Stephen Kearney led the US Army into the Mexican territory. Governor Armijo put in a brief appearance at the head of a ragtag militia defending Santa Fe, but then fled in fear with Guadalupe Miranda to Chihuahua. After the invasion, New Mexico was incorporated as a territory but because of its isolation and the hostility of the Apache Indians, the area attracted few settlers.

Unaffected by the US Army, Charles Beaubien stayed put, but his plans for developing the grant were ruined by the Taos revolt in 1847 against the US invaders. He turned the management of the grant over to his son, Narciso. However, both Narcisco and Beaubien's son-in-law, Stephen Lee were killed in the Taos Revolt by a loose coalition of Indians and Mexican patriots. Also killed in the revolt was Charles Bent, who had been appointed by the US Army to be New Mexico's civilian governor. Beaubien inherited his son's interest in the other grant.