For quasistatic stress problems two alternative constitutive relationships expressing the stress in a linear viscoelastic solid body as a linear functional of the strain are derived. In conjunction with the equations of equilibrium these form the mathematical models for the stress problems. These models are first discretized in the space domain using a finite element method and semi-discrete error estimates are presented corresponding to each constitutive relationship. Through the use respectively of quadrature rules and finite difference replacements each semi-discrete scheme is fully discretized into the time domain so that two practical algorithms suitable for the numerical stress analysis of linear viscoelastic solids are produced. The semi-discretes estimates are then also extended into the time domain to give spatially H1 error estimates for each alogrithm. The numerical schemes are predicated on exact analytical solutions for a simple model problem, and finally on design data for a real polymerical material.