The first instance of a figure of the lion as symbol of the Kingdom of León is found in minted coins of Alfonso VII, called the Emperor (1126–1157).
The Spanish historian and heraldist Martín de Riquer explained that the lion was already used as heraldic emblem in 1148.
The first reference to the lion as personal emblem of the monarch, and thus the kingdom find in Chronica Adefonsi imperatoris, at the times of Alfonso VII, this chronicle when describing participants armies in the taking of Almería, the text literally says: (...) the select order of knights from León.
One of the earliest known examples of armory as it subsequently came to be practiced decorates the tomb of Geoffrey Plantagenet, Count of Anjou, who died in 1151.
In favour of the second hypothesis is the fact that in the author of the Chronica made a rhyme with the words "legionis" and "leonis".
There are two exceptions, the lions rampant depicted on shields of Ferdinand II and Alfonso IX in their respective representations of the Tumbo A Manuscript of Santiago de Compostela Cathedral.
These cases show lions rampant, the reason is that the heraldic charges should always arranged in such a way that they take up the greater part of the field.
This also avoids horror vacui, dominant in the medieval art, filling of the entire surface of a space or an artwork with detail.
In the case of Alfonso IX, this lion is framed in a flag whose background is argent and has a narrow purple border.
In the beginning the Castilians used a simple cross until the Battle of Las Navas de Tolosa (1212) when Eleanor of England, wife of Alfonso VIII, designed the canting arms of the Kingdom of Castile: gules, a three towered castle or, masoned sable and ajouré azure.
After the Spanish Civil War, Juan José Fernández Uzquiza,[22] president of the Provincial Council, introduced in the arms of the province the tail facing the body of the lion.
The crimson flag with the royal arms in the center, proper of the Crown of Castile and the Hispanic Monarchy and it responds to a fairly late use.
Secondly, the first description of a similar standard was found by the writer and linguist Waldo Merino Rubio in the Act of February 18, 1789 of the Book of the Municipal Agreements (Filandón, Diario de León June 5, 1987).
Something back is the standard that is kept in the office of the Mayor of León with the arms of the city, with a lion Or and two small escutcheons at the edges embroidered on crimson damask.
According to the historian Ricardo Chao, this was the standard of the city of León and served as a model for the current Leonese flag in the nineteenth Century.