  Starting from suitable tableaux over finite dimensional Lie algebras, we
provide a scheme for producing involutive linear Pfaffian systems related to
various classes of submanifolds in homogeneous spaces which constitute
integrable systems. These include isothermic surfaces, Willmore surfaces, and
other classical soliton surfaces. Completely integrable equations such as the
G/G_0-system of Terng and the curved flat system of Ferus-Pedit may be obtained
as special cases of this construction. Some classes of surfaces in projective
differential geometry whose Gauss-Codazzi equations are associated with
tableaux over sl(4,R) are discussed.
