From the Roman sources, in the Corpus luris Civilis, until the Nineteenth-Century codifications, the fortuitous event was central both in Public Law and in Private Law. The study of the Castilian and Indian Laws Compilations and of Chapter XIX of Comentarios a las ordenanzas de minas, published by Francisco Xavier de Gamboa in 1701, will allow to emphasize how in the Indian Order recourse was made exclusively to the Siete Partidas to discipline this important legal category, even in the last decades of the XVIII Century.