CKCC Scholarly Correspondences stands for Circulation of Knowledge and Learned Practices in the 17th-century Dutch Republic. A web-based Humanities’ Collaboratory on Correspondences. The ePistolarium is a web application that enables visitors to browse through 20,000 digitalised letters. These letters, which are in different languages, were written by Dutch scholars from the seventeenth century, including for instance father and son Huygens. At the basis of the ePistolarium lie various language and visualisation techniques, via which researchers can create visible timelines and social networks. Also considering later letter collections in the archive, DANS has developed a methodology so that the research institute can automatically deposit structured datasets with different kinds of metadata.