Comparison of the results of a thin viscous sheet model with the velocity field determined by GPS stations in the Alpine-Pannonian realm shows that the Adriatic plate is only slightly stronger than the Eastern Alps. The observed velocity field is best approximated with a Newtonian fluid. However, this scenario must be fairly recent, as the overall geometry of the orogen can only be reproduced if the rheology contrast was about 1:10 before the late Miocene. The boundary conditions for this model are tested against the orientation of the intraplate stress field and are robust for Argand numbers between 1 and 5. We conclude that the convergence rate between the Adriatic and European plates must have slowed since the Miocene and that the present-day eastward extrusion of the Eastern Alps is largely due to lateral escape and only to a minor degree due to gravitational collapse. Scaled viscosities of the Eastern Alps are on the order of 1023 Pa s.