This inscription on white marble by Lucius Gavidius uses the term ther cultores to refer to his Mithraic community in Stabiae, Italy.
TNMM600
From Italy
Aug(usto) s[a]crum. / L. Gavidius A[…]t[…] / cultoribus dei M[i]thr[ae] / donum d(edit) d(edicavit) li[b(ens) me]r(ito).