W in my catchup quest - so THE BORGIA RING by Michael White - the second of his books I've read - Equinox was a while ago now.
From the Blurb:
When builders dig up an ancient skeleton in the City of London, they have no idea of the poisonous legacy they have just unleashed.
Opening Lines:
Prologue - Rome, August 1503. Pope Alexander VI had a lead like a huge scrotum. Grease dribbled down his chin and his unusually mean black pupils dilated as he contemplated the mountainous sweet pudding placed before him. His daughter Lucrezia Borgia looked at him and felt vomit rise in her throat.
For on the skeleton's finger is a beautiful emerald ring that once belonged to Lucrezia Borgia, the most powerful - and most evil - woman of the Renaissance.
Hours later the skeleton has vanished and one man is dead.
For DCI Jack Pendragon - newly transferred from Oxford to Brick Lane - it's a first case he could have done without. And with two more gruesome deaths in quick succession, it's clear there's a killer out there with a deadly compulsion.
A killer drawing his murderous inspiration from a 15th-century family whose cruelty and depravity knew no limits.