Is very important to know the origin of the languages we speak, in this case Spanish.
Spanish is derived from a dialect of spoken Latin evolved in the north-central part of the Iberian Peninsula after the fall of the Western Roman Empire in the fifth century. Castilian Spanish originated after the decline of the Roman Empire, as a continuation of spoken Latin.
Castellano (castilian) borrowed many words from Arabic after defeat by the Muslims in 711. The first steps toward written Castilian were taken in the 13th century by the King Alfonso X.
Cristóbal Colón
Antonio de Nebrija wrote the first grammar of Spanish in 1492. Nebrija gave his writing to Queen Isabel, as if anticipating the empire that was about to be founded with the voyages of Colombus.
Beginning in the 16th century, Spanish Colonization brought the language to the Americas (México, Central America, western and southern South America), where it is spoken today.
Cristóbal Colón (Christopher Columbus) was an Italian explorer, navigator and colonizer. He was a commissioned by the Catholic Monarch of Spain and completer four voyages across the  Atlantic Ocean that lead to general European awareness of the American Continents. Those voyages and his efforts to establish permanent settlements on the island of Hispaniola, initiated the Spanish Colonization of the New World.


Colón never knew that he had reached a continent previously unknown to Europeans. He thought he had reached the East Indies (India). Colón called the inhabitants of the lands he visited "Indios".

Here I found a video about the History, it has good information and examples about the changes Spanish had in its history.