I have been reading Spanish history today, and have noticed a very distinct commonality in the flags and coat of arms for various periods, but I haven't been able to find precise explanations of the mythology or meaning for the creature consistently depicted, see example attached.
This is from the flag of Leon, seems to be a phoenix, but I really have no clue.
Does anyone have more insight to share?
First, you should have your comments in the question itself, paraphrased accordingly.
Second, heraldry is an entire subject-matter, which requires expertise to understand the symbols.
Finally, in order to avoid anachronistic interpretations, we should be aware that bestiary during the medieval period was not precise (emphasis mine):
The bestiary was a popular genre of work in medieval Europe, especially during the twelfth and thirteenth centuries. Medieval bestiaries quite often describe ‘tigers’. It is very obvious that their authors had never seen a tiger and had very little idea what one was like. Tigers are usually described as having spots, and being able to run very fast, which would seem to indicate that the word ‘tiger’ was actually applied to the cheetah. Many bestiaries are illustrated, and the pictures commonly show a spotted animal, with no sign of any stripes. A manuscript now in the Bibliothèque Municipale de Douai (MS0711), in France, includes a depiction of a rather dog-like ‘tiger’, spotted all over with bicoloured rosettes.
Source: Haw, Stephen G.. “The Persian language in Yuan-dynasty China: a reappraisal.” (2014).
This was about tigers, not lions but it applies all the same. Morphological precision was not their forte.
I may note that the purple lion is a sort of a heraldic pun, which is termed a canting coat of arms.
https://en.wikipedia.org/wiki/Canting_arms1
https://www.heraldica.org/topics/canting.htm
Many persons who adopted coats of arms designed them as puns on their family names. Many persons adopted family names after adopting coats of arms, and sometimes they based their family names on their coats of arms.
In Hamlet the fictional characters Rozencrantz and Guildenstern have the names of real noble Danish families. The name Rozenkrantz means rose wreath or rosary and the Rosencrantz coat of arms has a wreath of rose between the helmet and the crest instead of the usual wreath or torse. Guildenstern means golden star and the Guildenstern coat of arms has a gold star.
Rosenkrantz can be translated as rose wreath or rosary. The family's name appears to be derived from the coat of arms, in which we find a wreath of heraldic roses instead of the usual torse between the helm and the crest.2
https://en.wikipedia.org/wiki/Rosenkrantz_(noble_family)3
Gyldenstjerne, also spelled Gyldenstierne and in Swedish Gyllenstierna (English: Golden Star), is a Danish, Norwegian, and Swedish noble family divided into various branches and ranks. It is one of the oldest noble families in Scandinavia.
The family surname appears, in the form of Guildenstern, in William Shakespeare's tragedy The Tragedy of Hamlet, Prince of Denmark (see Rosencrantz and Guildenstern).
The Gyldenstjerne coat of arms is blue with a gold seven pointed star.
https://en.wikipedia.org/wiki/Gyldenstierne_(noble_family)4
So either the Gyldenstjerne name is based on the Gyldenstjerne coat of arms, or the Gyldenstjerne coat of arms is based on the Gyldenstjerne name.
The white coat of arms with a strange purple animal is the coat of arms of the former Kingdom of Leon. The animal is a heraldic lion in the rampant position.
https://en.wikipedia.org/wiki/Lion_(heraldry)5
The Kingdom of Leon was named for the main city of Leon.
Its modern name, León, is derived from the city's Latin name Castra Legionis.6
The Spanish word Leon means lion.
https://www.indifferentlanguages.com/words/lion6
So clearly the lion coat of arms of the City of Leon and the former Kingdom of Leon is a Spanish language pun.
https://en.wikipedia.org/wiki/Heraldry_of_Le%C3%B3n7
The coat of arms of the former Kingdom of Castile is red with a gold three towered castle. Castillo in Spanish means castle.
https://www.indifferentlanguages.com/words/castle8
https://en.wikipedia.org/wiki/Heraldry_of_Castile9
https://en.wikipedia.org/wiki/Coat_of_arms_of_Castile_and_Le%C3%B3n10
So even institutions as important and serious as kingdoms can have coats of arms that are visual puns.
