The study assesses the main issues in the current debate about the early history of Pesach and Easter and provides new insights into the development of these two festivals. The author argues that the prescriptions of Exodus 12 provide the celebration of the Pesach in Jerusalem with an etiological background in order to connect the pilgrim festival with the story of the Exodus. The thesis that the Christian Easter evolved as a festival against a Jewish form of celebrating Pesach in the second century and that the development of Easter Sunday is dependent upon this custom is endorsed by the author's close study of relevant texts such as the Haggada of Pesach; the "Poem of the four nights" in the Palestinian Targum Tradition; the structure of the Easter vigil.