In early 1923, the residents of Greece experienced a significant change when they went to sleep on February 15 and woke up on March 1, due to the country's switch from the Julian calendar to the Gregorian calendar. This adjustment involved a 13-day difference between the two systems. The Julian calendar, established by Julius Caesar in 44 BC, was widely used until the Gregorian reform introduced by Pope Gregory XIII in October 1582 aimed to better align the calendar with the astronomical year.

The transition from the Julian to the Gregorian calendar was not just a straightforward adjustment of dates; it also carried implications for religious observances, civil activities, and the synchronization of the country's timekeeping with international standards. The introduction of the Gregorian calendar allowed Greece to align itself more closely with continental Europe, which had mostly adopted this system by that time.

Despite its practical benefits, the change also led to confusion among the population, as many people were accustomed to the Julian calendar and the traditions built around it. The article explores these historical details, the rationale behind the change, and its broader impacts on Greek society during the early 20th century.