The coinage of the emperor Postumus (AD260-69) included an aureus of unique reverse type depicting three draped and radiate busts in a row, with the centre bust facing forward while the two busts on either side face sideways towards it. It is argued that this depicts three busts of Sol and was intended to symbolize the apparent appearance of three suns in the sky, as described, for example by Pliny the Elder (NH 2.99), that is, the occurrence of a solar halo. A number of other coins almost certainly commemorate similar events, although not in the same way, from issues by Mark Antony in 42BC to issues under Constantine I from 310.