Help needed with unknown Coat of Arms

Mar 2019
Patrai Greece
Dear friends
Thanks for letting me join your forum. I will need your help with an identification of coat of arms in a signet ring. My Grand father gave it to me 20 years ago and i am searching to find out the history of it.
I am writing you from Patras Greece and i believe that this is from Frankish Era or Venetian Rullers.
Thank you .