Carausius. Romano-British Emperor, AD 286-293. Antoninianus (18mm, 1.76 g, 12h). 'RSR' mint. Radiate, draped, and cuirassed bust right / CONCOR[...], clasped hands; RSR. Cf. RIC V 602-4. Rough green patina. Near VF. Rare.
From the Northwest Collection.
This mintmark has yet to be positively identified, but see de la Bédoyère, "Carausius and the Marks RSR and I.N.P.C.D.A.," NC 1998, for an interpretation of RSR as a quote from Vergil's Eclogues iv.6-7: Redeunt Saturnia Regna, and the placement of the issue at London.