The political, social and financial situation of Portugal during the 19th century provided that, in many ways, conventual heritage was the object of acts that contributed to its ruin. The lack of incomes, the French invasions, the civil war, the General Ecclesiastical Reform, the extinction of religious orders (1834) and the disentailment of their properties, the closure of the female convents, the complex state management, were, among others, the favourable conditions to the development of attitudes that fit into what we usually call vandalism. Important monuments such as the monasteries of Alcobaça or Santa Maria de Belém would not escape to negligence, destruction, decontextualization. The records left by some 19th century intellectuals, and documentary sources such as these presented, some unpublished, are shown indispensable to understand the several aspects of vandalism in the convents and their spoils, important nuclei of the national architectural and artistic heritage.