In 1903, after the census had been taken, San Ildefonso (pop. 5326) was annexed to San Miguel.
At this time there was much uneasiness in the United States as a result of Spain's restoration of Louisiana to France by the secret treaty of San Ildefonso, in October 1800; and the subsequent withdrawal of the " right of deposit " at New Orleans by the Spanish intendant greatly increased this feeling and led to much talk of war.
The college of San Ildefonso, completed in 1583, was the chief university building.
The royal glass manufactory of La Granja de San Ildefonso was founded about 1725; in the first instance for the manufacture of mirror plates, but subsequently for the production of vases and table-ware in the French style.
6° 52' 15" S., which is half the distance between the mouth of the Mamore and the mouth of the Madeira, divides the Spanish and Portuguese possessions in this part of South America, according to the provisions of the treaty of San Ildefonso of 1777.
Other plants are at San Ildefonso, 12 m.
A little farther away are the woollen mills of San Ildefonso, the paper-mills of San Rafael, and important works for the manufacture of railway rolling stock.
FERDINAND VII., king of Spain (1784-1833), the eldest son of Charles IV., king of Spain, and of his wife Maria Louisa of Parma, was born at the palace of San Ildefonso near Balsain in the Somosierra hills, on the 14th of October 1784.
The controversy with Spain was amicably settled by the treaty of San Ildefonso (1777); and further industrial and educational reforms were inaugurated, chief among them being the foundation, in 1780, of the Royal Academy of Sciences.
The boundary line between Bolivia and Brazil has its origin in the limits between the Spanish and Portuguese colonies determined by the treaties of Madrid and San Ildefonso (1750 and 1777), which were modified by the treaties of 1867 and 1903.