Summary: This paper describes the MATHESIS semantic authoring framework being developed within the MATHESIS project. The project aims at an intelligent authoring environment for reusable model-tracing tutors. The framework has three components: an intelligent web-based model-tracing algebra tutor, an ontology and a set of authoring tools. The tutor serves as a prototype for the development of the ontology. The purpose of the ontology is to provide a semantic and therefore inspectable and re-usable representation of the declarative and procedural authoring knowledge necessary for the development of any model-tracing tutor, as well as of the declarative and procedural knowledge of the specific tutor under development. The procedural knowledge is represented via the process model of the OWL-S web services description ontology. Based on such an ontological representation, a suite of authoring tools is being developed at the final stage of the project.