This tauroctony is embedded in the wall of a renaissance palazzo in Rome. From Twitter:
The courtyard of Palazzo Mattei di Giovanni, is a treasure trove of #spolia. Anthony @antmoose has pointed out that some of the intricate panels are from #sarcophagus fronts (probably not the Mithras panel) - Heidi (@caputmundiHeidi).
CIMRM entry
534
White marble relief (H. 0.95 Br. 1.85), walled in the Palazzo Mattei under the arches of the inner court, to the right of the entrance.
Monumenta Matheiana, Roma 1778, III, Pl. 1; Turre, Mon. Vet. Antii, 159; Zoega, Abh., 149 No. 22; Matz-v. Duhn III, 141 No. 3756; MMM II 218f No. 47 and fig. 49; RRR III, 299, 2. See fig. 150.
In a cave Mithras in the usual attitude and attire, slaying the bull. The dog and the serpent near the wound; the scorpion at the testicles; the raven on the rocky cave. Cautes with upraised torch stands behind the bull; Cautopates on the other side with his torch downwards. Both are cross-legged.
The upper half of the relief is restored: Mithras’ head; the upper border of the cave and two trees; the globe, on which the dog is standing; the greater part of the serpent. Mithras’ dagger and a part of Cautopates’ torch have got lost.