The correlator of heavy-quark currents is calculated in quenched Lattice QCD on a 16(3) x 32-lattice for beta = {6, 6.3}. The renormalized charmed quark mass is extracted from the short-distance part of that correlator: m(c)(<(MS)over bar>)(m(c)) = 1.22(5) GeV. We study the sensitivity of our data to the strong coupling constant.