  We study linear integro-differential equations in Hilbert spaces with
operator-valued kernels and give sufficient conditions for the well-posedness.
We show that several types of integro-differential equations are covered by the
class of evolutionary equations introduced in [R. Picard. A structural
observation for linear material laws in classical mathematical physics. Math.
Methods Appl. Sci., 32(14):1768-1803, 2009]. We therefore give criteria for the
well-posedness within this framework. As an example we apply our results to the
equations of visco-elasticity.
