In the 'Longmire' episode "Death Came In Like Thunder", the three Vayas brothers had been tending the mountanside where their family had been shepherds for nearly ninety years. That is, until youngest brother Marco was murdered for trying to sell his share....
The grandparents of Marco Vayas and his brothers Costa and Sal had been the only survivors of their family when Franco allowed Hitler to enter the town of Guernica and use its citizens for "target practice". The couple escaped and fled to America with nothing to show for their past life in that Basque enclave.
It's pozz'ble, just pozz'ble, that they eventually arrived in the area of Stockton, California, where there was a Basque community. There they would have moved on with other Basque families to Absaroka County in Wyoming. Once they established their home and began a family, their son may have married into either the Ariata or De Navarre families, both of whom had ancestors who were involved in a controversial court case back in Stockton sometime after 1876.
FRANCISCO DE NAVARRE
Jarrod defends a Basque Sheepherder accused of murder. He is in more than providing a defense when he finds out his client is a political anarchist in a town full of bigotry and hate. (IMDb)
Can't be proven; can't be disproved either. So it's a viable theory of relateeveety.