Made by a military mint travelling with Brutus during the late summer or autumn of 42BC, the coin (best known from around 80 surviving silver denarii) has long fascinated both numismatists and historians.
The simple reverse design contains the three principal elements used to kill a dictator: the pileus or cap of liberty and two daggers of differing design, one symbolising that wielded by Brutus himself on March 15, 44BC, the other that of Cassius, his co-conspirator. The legend Eid Mar abbreviates Eidibus Martiis – the Ides of March.
Until recently it was thought that the coins in the British Museum and the Deutsche Bundesbank collection were the only two surviving gold examples of this famous issue. This new discovery has a 19th century Swiss provenance, having descended in the family of the antiquarian Baron Gustave Charles Ferdinand von Bonstetten (1816-92).
The winning bid was more than five times the top estimate and around £3.25m with the 20% premium added.
The previous record for a classical coin was a Pantikapaion ‘satyr head’ gold stater sold for $3.25m (£2.3m) at the Prospero sale in New York in 2012.
The buyer's premium was 20%.