Exploring ways to bring material interest to a watch dial is as old as timekeeping itself. And one of the most interesting ways to add face value has been using coins - either as a dial or as the entire case. Rare versions of pocket and wristwatches from Patek Philippe, Vacheron Constantin and Audemars Piguet featuring currencies from the US, Switzerland, France and Mexico have all raised their heads at auction.
Piaget's acclaimed Dalí D'or watches and jewellery use the coins Salvador Dalí minted in the 1960s and 1970s incorporating like-nesses of himself and his wife Gala. Among the most prolific are the Corum Coin Watches using gold dollar coins and worn by US presidents including Richard Nixon, Jimmy Carter, Ronald Reagan and Bill Clinton. Even Andy Warhol had a Corum Coin Watch in his celebrated collection.
Some of the most desirable of coin watches and jewellery are Bulgari's Monete pieces, which have showcased ancient coins from Greece, Persia and, of course, Rome. First appearing in the 1960s, they have been worn by celebrities from Grace Kelly to Candice Bergen and are particularly associated with Elizabeth Taylor, thanks to the gourmette sautoir with six Byzantine coins that she often wore.
The watches are rare, due to sourcing the antique coins. But this summer will see two new Octo Roma Monete watches unveiled, with ultra-slim skeleton flying tourbillon movements and 44mm octagonal cases - one in rose gold, one in platinum - surrounding silver Constans Medallions, which act as dial covers that open via the winding crown.
The two medallions hail from a time of turbulence in the Roman Empire following the death of Constantine the Great in 337AD, when his sons - Constantine II, Constans and Constantius II - co-ruled.
The medallion in the rose-gold Octo was minted in honour of their investiture and shows a bust of Constans on the front. The medallion for the platinum version also shows Constans, while the reverse bears the inscription: "TRIVMFATOR GENTIVM BARBARARVM" (triumphator over the barbarian nations).
A third piece will be a Monete high-jewellery pendant secret watch in a 41mm octagonal case decorated with coral and diamonds and an ancient silver Greek coin from 2BC.
Price on application; bulgari.com
Sign up for the Telegraph Luxury newsletter for your weekly dose of exquisite taste and expert opinion.