This dataset, which is the product of a master's dissertation (https://hdl.handle.net/10216/143034), analyzed a sample of 25 records from the Portuguese National Archives (https://digitarq.arquivos.pt/), chosen by archival specialists as representative of different fonds and description levels, to identify entities and properties and explore relationships with other non-archival resources. After selecting the entities in the records, Wikidata and DBpedia databases were chosen for data enrichment and linking. The analysis of the entities in the records provided hundreds of properties directly related to classes in the corresponding databases. A more significant set of properties was obtained by selecting properties that had more data entered into the databases for entities of the corresponding classes. These entities and properties were then subjected to tests using Wikidata Query Service and DBpedia SPARQL Explorer. The goal of this data generation was to provide additional information to improve the search interfaces of archival information systems helping to optimize information retrieval to the benefit of archivists and users.