This is one of William's latest rings, it's set with a rutilated quartz which he hand carved a skull into the back of. It has MEMENTO MORI (Remember that thou shalt die) written in Latin around the band.
These kind of rings were extremely popular right up to the beginning of the 20th century.
Here are some other examples of solemn messages which have been found on skull (or death's head) rings from the 15th and 16th centuries.
RESPICE FINEM SAPIENS ESTO (It is wise to contemplate the end)
MORI SAEPE COGITA (Think often of death)
This one is not strictly of this death's head vein but I like it,
CREDE ET VICISTI (Believe and thou hast conquered)
The Latin phrases used for love and marriage rings are really lovely too, I think I'll do another post on them later.
See more of William's jewellery HERE
There are plenty of pictures on the Metal Couture Facebook page too.