We present and analyze the results of a connectionist simulation which modeled the reanalysis of the Latin gender system in its transition to Old French. The network reanalysis was based solely on formal cues (word endings and analogy with other words) and on frequency. The results are in accordance with the historical data, and certain errors in simulations are also amenable to principled explanations. Simulations improve dramatically when the networks incorporate information about the Celtic substrate which presumably interfered with gender assignment in Gallo-Romance. This finding has a bearing on issues of gender assignment and processing in bilinguals. Simulations also improve with the introduction of more elaborate recurrent networks, which suggests implications for future connectionist modeling. In particular, the results could be applied to the modeling of gender change in other Romance languages and to the modeling of comparative Romance gender systems. The method proposed here would be advantageous for such simulations since it allows the modeler to take into account a rich variety of facts reflecting actual linguistic history.