Libretto, (in English: booklet) plural librettos or libretti, text of an opera, operetta, or other kind of musical theatre. It is also used, less commonly, for a musical work not intended for the stage. A libretto may be in verse or in prose; it may be specially designed for a particular composer, or it may provide raw material for several; it may be wholly original or an adaptation of an existing play or novel. Writing a libretti demands techniques different from those for writing spoken drama. Music moves at a slower pace than speech, and an orchestra can suggest emotions that would need to be made explicit in a play.

The Fondo Ulderico Rolandi is one of the greatest collections of libretti (text booklet of an opera) in the world. This collection of libretti which is in the possession of the Fondazione Cini consist of around 32,000 thousand libretti, spanning a time period from the 16th to the 20th century. This collection is being digitized and made accessible to the public in the online archives of the Fondazione Cini, where currently 1,110 libretti are available.

The Rolandi Libretti can be considered as a collection of many unstructured documents, where each document describes an opera performance. Each document contains structured entity information about place, time and people (e.g.: composer, actors) who were involved in this opera. In our project, we want to extract as much entity information about the operas as possible. This includes information as the title of the opera, when and in which city it was performed, who was the composer, etc. By extracting the entity information and linking it to internal and external entities, it is possible to construct one comprehensive data set which describes the Rolandi Collection.

The linking of information to external entities, would allow us to connect our data set to the real world. This would for example include linking every city name to a real place and assigning geographical coordinates (longitude and latitude) to it. Constructing links in the data set as such, would allow us for example to trace popular operas which were played several times in different places or famous directors which directed many operas in different places. In a last step we want to construct one comprehensive end product which represents Rolandi Collection as a whole. Thus we want to visualize the distribution of operas libretti in space and time and potentially construct indications of linking.