Britannicus was the son of Claudius and presumptive heir to the throne until Agrippina showed up with her own son Nero. Between the two they plotted to eliminate Britannicus and managed to poison him just like they had his father.
RIC unlisted, BMC 226 (Claudius) & 306 (Titus), C 2 Sestertius Obv: TICLAVDIVSCAESARAVGFBRITANNICVS - Bare-headed, draped bust left.
Rev: No legend - Mars advancing left, holding spear and shield. c.50-54 (Rome). $8,600 9/24/03.