Answer: Julius Caesar.
Some extra relevant information:
The Julian calendar, named after Julius Caesar, was implemented in Rome during his reign. As one of the most renowned leaders in history, Julius Caesar contributed significantly to the Roman Empire, not only as a military general and politician but also in the realm of calendar reform.
Before the Julian calendar, the Roman calendar was based on lunar cycles, which often led to inaccuracies and confusion. Recognizing the need for a more accurate and standardized system, Caesar sought to reform the calendar.
With the assistance of the Alexandrian astronomer Sosigenes, Julius Caesar introduced the Julian calendar in 45 BCE. This calendar was based on the solar year, with 365 days divided into twelve months. Additionally, every four years, an extra day, known as a leap day, was added in February to account for the slight discrepancy in the actual solar year.
The implementation of the Julian calendar brought about several significant changes. It marked January 1st as the start of the year, a tradition that is still followed today in many parts of the world. Previously, the Roman calendar had begun on March 1st.
Julius Caesar’s reforms also aimed to align the calendar with the agricultural cycle and religious festivals, ensuring more accurate timings for important events. The Julian calendar became the standard calendar in Rome and later spread throughout the Roman Empire, significantly improving the measurement of time.
Overall, the implementation of the Julian calendar in Rome by Julius Caesar demonstrates his visionary leadership and commitment to enhancing the functionality of the Roman Empire. This calendar reform played a crucial role in shaping the modern calendars we use today.