This paper presents the results of an experiment to decide the question of authenticity of the supposedly spurious Rhesus - a attic tragedy sometimes credited to Euripides. The experiment involves use of statistics in order to test whether significant deviations in the distribution of word categories between Rhesus and the other works of Euripides can or cannot be found. To count frequencies of word categories in the corpus, a part-of-speech-tagger for Greek has been implemented. Some special techniques for reducing the problem of sparse data are used resulting in an accuracy of ca. 96.6%.