I’m new to this forum and have been collecting ancient and medieval coins for 30 years. Lately have been focusing on Anglo Saxon silver pennies and Celtic coins of all types. I recently purchased the coin pictured and need some help identifying. It seems to be a double strike on both sides or a broken die. I think the ruler may be Ethelred I based on the setup of the reverse, but not positive. Any ideas, and are these types of errors common with these types of coins?