The lion design is attributed to Alfonso VII,[1] who became king of Castile and León in 1126.

The castle symbol is attributed to his grandson Alfonso VIII,[1] In 1230, Ferdinand III united the two kingdoms and quartered the arms as a symbol of the union.

[1] Until the sixteenth century, a full castle, with walls and three towers, rather than the current town design, was used.

[2] Like Lyon in France, the name of the city of León has no link with the animal lion, as it comes from the Latin word legio (legion).

Its original elements are used not only in the current autonomous community of Castilla y León, but also in the national coat of arms of Spain, in municipal arms like the coat of arms of Toledo and in coats of arms of many former territories which belonged to the Crown of Castile, such as Jaén or Los Angeles, California.