Steel
More than sixty years after Coronado explored the region that would become New Mexico, the Spanish returned, establishing San Juan de los Caballeros in 1598, Santa Fe in 1610, and Taos in 1615. They conquered the Pueblo Indians and colonized them with missions and military garrisons, intending to remake their culture into that of Spanish peasants separate and apart from other Indians. Unwittingly, these European newcomers created a new dynamic on the southern plains.
Surrounding this region were a fairly recent group of immigrants, the Apaches and another Athabaskan speaking group, the Diné, or Navajos. The presence of the Spanish caused the Apaches to shift from a trading relationship with the Pueblo towns to relying more on raiding and plundering. Likewise, the Spanish presence attracted raids from other groups including Utes to the northwest.
These attacks introduced a trickle of plundered Spanish livestock and goods into the Great Basin and Great Plains. These exotic goods and animals served to lure even more native attention on the Spanish settlements. Items as mundane as pots and pans, knives, and scrap steel (like barrel bands and horseshoes) became highly prized as they represented rare luxuries for the Indians. Spanish weapons, when acquired, changed the balance of power as these natives jostled for position to be close to the sources of these new wonders.