Introduction 
IT 
where, as early as 1548, rich lodes had been discovered. A number of 
settlements, among them being Matehuala, San Gerónimo, and Charcas 
Vieja, were soon founded; in 1576 the town of San Luís Potosí was 
founded and became the seat of an alcaldía mayor with extensive juris¬ 
diction to the north. 
Meanwhile, however, the frontier had advanced much further north¬ 
ward. In 1554 Urdiñola founded Mazapil and opened up, nearby, the 
famous Bonanza mine. The next year the new province of Charcas was 
created with Urdiñola as alcalde mayor. This province, which included 
the settlements of Matehuala and Tula, extended on the west as far as 
Fresnillo and San Martin and on the north to Zapalinamé. Under Urdi¬ 
ñola development was rapid. In July, 1555, he established the presidio 
of Santiago del Ojo de Agua del Saltillo, which became the centre for a 
number of small settlements. The same month an expedition reached 
present Monterey. 
Urdiñola died in January, 1556, and the viceroy appointed as his suc¬ 
cessor Francisco de Ibarra, whom he then contemplated appointing gov¬ 
ernor and captain-general of New Mexico and the Seven Cities. Ibarra 
was employed until 1559 in extending his conquests from Zacatecas to the 
Rio Nazas. In the latter year he visited the settlements in Charcas and 
on February 2, 1559, elevated the presidio of Saltillo to a villa with the 
appellation of Santiago del Saltillo. Leaving there his lieutenant alcalde 
mayor, Ibarra visited Mazapil, Matehuala, and Tula before returning to 
the Rio Nazas settlements in March. Soon afterward all of the territory 
north of Zacatecas, including the alcaldía mayor of Charcas, was erected 
into the new province of Nueva Vizcaya with Francisco de Ibarra as gov¬ 
ernor. His interests, as outlined above, soon led him to the north and 
west of Durango. 
In 1575 Francisco de Urdiñola, the younger, just out of college in 
Europe and heir to the rich mines opened up by his father, offered to ex¬ 
tend, at his own expense, the conquests and carry on the colonizing work 
begun by his father in the region to the north of Mazapil and Saltillo. 
The viceroy accepted the proffer and by Urdiñola satisfactory peace terms 
were finally arranged with the bellicose Guachichiles Indians, and pueblos, 
both of Spaniards and of Indians, were established. At San Francisco de 
los Patos, in the Laguna region, Urdiñola founded, in 1575, a Spanish 
garrison and settlement. Still further west he established three large 
private estancias, the most pretentious of which was San Pedro del Alamo. 
This became the centre of a veritable garden spot, and there, in addition 
to extensive corrals and the quarters for the Spaniards, Tlascaltecans, and 
slaves, a pretentious chapel was begun. 
Later, on August n, 1591, Urdiñola was commissioned by Rodrigo del 
Río de Losa, then governor of Nueva Vizcaya, as his lieutenant governor 
and captain-general at Saltillo, in which capacity he served for a number 
of years. In September and October, 1591, Urdiñola carried out the 
instructions of the governor and the viceroy when he founded at Saltillo 
