I have a rather crude-looking majorka style mug with a corn design and a very blurred, green mark. I've never seen this mark before and would like to know where the mug is from.

The mark is shaped like a medallion, with what looks like a (viking?) ship with five rowers or dragon heads onboard. There's a row of holes (shields?) on the side of the ship. There are two circles around the design, with unintelligible text between them. There may be something like a crown or tiara-like shape on top of it all.

Can anyone please help?

Thank you in advance.