The OPERASAMPO is a Linked Open Data (LOD) service and semantic portal for searching, browsing, and analyzing information related to historical opera and music theatre performances performed in Finland during 1830–1960. The key data originates from the Reprises database of the Sibelius Academy, Finland. This paper presents the process of transforming the original data into LOD and the data model created for it, data maintenance, as well as the portal and data service for utilizing the data. The novelty of OPERASAMPO lays on its focus on studying data about the musical performances and persons involved in different roles using faceted search and browsing combined seamlessly with data-analytic tools for Digital Humanities research. The service was published for open use in October 2023.