This paper investigates the price war in the UK quality newspaper industry in the 1990s. We build a model of the newspaper market which encompasses demand for differentiated products on both, the readers and advertisers side of the market, and profi…t maximization by four competing oligopolistic editors who recognize the existence of an indirect network effect of circulation on advertising demand. Editors choose fi…rst the political position, then simultaneously cover prices and advertising tarifs. We contribute to the literature on two-sided markets by endogenizing the political differentiation of newspapers in a model with more than two …firms. We simulate changes to market structure in order to explore which of the candidate explanations is most likely to lie behind the observed price war