We develop a complete local wellposedness theory for a Maxwell system on \(\mathbb {R}^3\) and a large class of nonlinear material laws which are nonlocal in time. Such constitutive relations are typical for nonlinear optics. The problem was treated before in the Sobolev space \(H^s\) for \(s>3/2\) by means of energy methods. Using a recently shown Strichartz estimate, we can lower this level of regularity to \(s>1\) . In this context ’charge-type’ terms would spoil the analysis. We avoid them by the Helmholtz projection for the divergence operator with coefficients, which requires mapping properties of the projection also in \(H^{\alpha , q}\) with \(q\ne 2\) .