Perfektkonstruktionen mit haben und sein : eine Korpusuntersuchung im Althochdeutschen Altsächsischen und Neuhochdeutschen This study examines German perfect constructions from a usage based perspective by carrying out a meticulous empirical investigation in two time frames. It analyzes all perfect tense forms in major early Old High German and Old Saxon textual monuments and their degree of grammaticalization. Then by means of an extensive corpus examination it shows the schemata behind contemporary German helper verb selection in the perfect tense.