What was the day on 01 January 0001?

In the Gregorian calendar system, the date January 1, 0001, corresponds to a Monday. However, it is important to note that the year 0001 is not considered a valid year in historical records, as the Gregorian calendar was not in use at that time. The calendar system commonly used during that period was the Julian calendar, which did not have a year 0, leading directly from 1 BCE to 1 CE.