From typicallyspanish.com

History
Spain On This Day - April 12
By m.p.
Apr 12, 2008 - 7:59 AM

1779: the Treaty of Aranjuez is signed by Spain and France, under whose terms Spain later joined the American War of Independence against Britain.

1931: municipal elections held in Spain give a resounding victory to the Republicans. Two days later King Alfonso XIII leaves Spain and the Second Spanish Republic is proclaimed.

1962: a law on the banking sector includes as an important part of the reforms the nationalisation of the Bank of Spain. The Bank was nationalised in June that year.

The operatic soprano, Montserrat Caballé, was born in Barcelona on this day in 1933, and the actor Álex Angulo in Erandio, Vizcaya, in 1953. Carlos Sainz, the former World Rally Champion, was born in Madrid 9 years later, in 1962.

Juana la Loca, Juana I de Castilla, died in the castle in Tordesillas which had been her prison for many years in 1555.