Abstract
Monte Carlo calculations have been carried out which distinguish between long-range and short-range parameters of a model consisting of classical Heisenberg spins arranged on a square lattice and coupled by an isotropic nearest-neighbor exchange. It is found that those standardly computed thermodynamic properties which depend primarily on short-range correlations are independent of the initial spin configuration and confirm the predictions of high-temperature series expansions. Nonuniqueness of long-range parameters, however, indicates the presence of metastable states.