Jacob Lorhard's ontology: a 17th century hypertext on the reality and temporality of the world of intelligibles Henrik Schärfe, Sara L. Uckelman Abstract: Abstract. Jacob Lorhard published his ontology in 1606. In this work the term ontologia 'ontology' was used for the first time ever. In this paper, it is argued that Lorhard's ontology provides a useful key to the understanding of the early 17th-century world view in Protestant Europe. Among other things, Lorhard's ontology reflects how the relations between scientific investigation and religious belief were seen. It is also argued that several of the conceptual choices which Lorhard made in order to establish his ontology may still be relevant for modern makers of ontological systems. In particular, Lorhard's considerations on the notions of reality and time deserve modern reflections. Also his assumption of the educational value of diagrammatical ontology deserves a modern discussion. Along with this paper an online hypertext version of Lorhard's ontology has been presented in order to create a useful tool for historical research in early 17th-century thought and in order to illustrate the problems, which characterized the early attempt at establishing a diagrammatical approach to ontology.