It certainly replaced the Jewish calendar and holidays (and the commandments and rituals for each).
Regarding the calender, it certainly changed when they had the number of days in the year figured out. Is the Jewish calender the same as it always was? did they have to add days or months to their year?
Even between eastern and western Christendom the Easter holiday is different. Most of the Jewish ethos is maintained in the New Testament but Grace and Mercy are emphasized more. Stoning is no longer as popular as it once was, how do the Torah respecting Jews handle some of the prescriptions for infractions found in the Old Testament?