Royal Emblem on one of the cannons. This is the only cannon in Castillo San Lorenzo that has this. If anyone has any information on this seal mail me!
I got an e-mail Last week about the logo:
The royal cypher shown on the cannon is the monogram of King George II, King of England, who reigned from June 11,1727 to October 25 of 1760, when he died at the age of 77. I possess a book about cannon, and I found the very same image as that in your photo. The script is GR, which stands for"Georgius Rex" which is latin for King George,I know that you will have a difficult time trying to see the "G" in the script, but if you carefully trace the first letter(on the left), you will see how the tail of the "R" intertwines around the tail of the "G", and if you look near the top of the "G", you will find the numeral "2"intertwined around curve of the "G".The "2" designates him as George II, as opposed to his father, George I,and I think his son, George III. (there were (3) Georges). This cannon could have been from one of Henry Morgan's ships, when he was privateering for England in the Portobello area, in the 1769/1771 era. It was also during this time that he attacked Fort San Lorenzo. I hope that this helps to clear up the mystery.