Tom sent us this picture of his gorgeous Juana y Carlos gold escudo from Spain. King Carlos I (Charles, Carol, Carolus, Carolvs, Karolvs and other spellings appear on the coin) was King of Spain from 1516 to 1566. His name and shield appears on one side of the coin, and Hispan (Espana, Spain) appears on the other, although the letters often get cut off the coin during the process of making it the correct weight.
Juana (Joan, Joanna, Ioana) was Carlos' mother and co-regent. Her name also appears on the coin, although reading any of these names is difficult.
History buffs are directed to this Wikipedia page which shows Carlos as Charles V of the Holy Roman Empire.
Finding values for these coins involves looking for auctions in which they have sold. I have seen auctions with hammer prices of $500 to $1500 US dollars, with the higher values going to coins with better eye appeal. Each coin stands on its own merits, especially in the area of eye appeal. As such we can give only very approximate estimates of value:
worn: $700 US dollars approximate catalog value
average circulated: $1000
well preserved: $3000
The large picture at the bottom of this page comes from Ira and Larry Goldberg where it sold for $775 US dollars in a 2012 auction. Thanks to the Goldberg's for letting us use their photo of this nice coin.
Tom's coin, pictured with the ruler, is in beautiful shape and appears to be genuine (not a counterfeit). Since the eye appeal is superb, the retail value of Tom's coin may reach toward the $2000 mark.