We perform knowledge discovery in software archives in order to detect refactorings on the level of classes and methods. Our REFVIS prototype finds these refactorings in CVS repositories and relates them to transactions. Additionally, REFVIS relates movements of methods to the class inheritance hierarchy of the analyzed project. REFVIS creates visualizations that show these refactorings in two different layouts and uses color-coding to distinguish between different kinds of refactorings. Moreover, our visualizations are interactive as they can be zoomed, scrolled and filtered; mouse-over-tooltips allow to examine details of the particular refactoring on demand. Categories and Subject Descriptors D.2 [Software Engineering]: Miscellaneous; K.6.3 [Software Management]: Software maintenance Keywords CVS, Data Extraction, Refactorings, Visualization