The year was 1576, and Pope Gregory XIII was holding a document in his hands that promised to solve a 1,620-year-old problem. The dilemma was essentially over how to repair the Julian calendar—itself an attempt to “solve” an issue with an older system—so it would stay in sync with the seasons.
When the Julian calendar was introduced in 45 BC, it replaced the previous Roman (or Republican) calendar that was based on both the sun and the moon. The Julian calendar simplified things considerably by completely abandoning the lunar cycles of that previous Roman system.
The result was a calendar that looked a lot like the calendar of today—just with different rules for leap years. Those rules, which Julius Caesar introduced with his calendar reform, were based on his inaccurate understanding that a solar year is exactly 365.25 days long. Therefore, a calendar that was 365 days long was used for three years, and every fourth year, without exception, a leap day was added to February.
For its first several centuries, the problem with the Julian calendar wasn’t apparent, but by the 1500s the calendar was ten days out of sync. For those who celebrated Easter, this meant that on the calendar their holiday was occurring further and further away from the spring equinox. Unless the Pope took action, Easter would eventually be celebrated in the summer instead of the spring. Since Easter was inextricably tied to spring and its agricultural rebirth, this was an enormous crisis that precipitated the institution of the Gregorian calendar.
In 1576, the framework for what came to be called the Gregorian calendar (though primarily developed by Aloysius Lilius) was ready for papal evaluation. Pope Gregory XIII appointed a Papal Calendar Reform Commission to analyze it, and six years later the calendar now used in most countries around the world was introduced by way of the papal bull Inter gravissimas. Initially adopted by the Roman Catholic countries of Europe and their colonies around the world, its usage and reach have continued to spread—most recently in 2016 to the Kingdom of Saudi Arabia.
God’s Timetable
Genesis 1 introduces us to different aspects of the creation, including the concept of time. “Then God said, ‘Let there be light’; and there was light. And God saw the light, that it was good; and God divided the light from the darkness. God called the light Day, and the darkness He called Night. So the evening and the morning were the first day” (vv. 3–5). The first aspect of the creation that we are introduced to is the most basic unit of the calendar. Here we learn that the counting of this daily cycle begins at sundown. The day is the foundation for marking time.
On day four of the recreation week, we are introduced to annual cycles of time.
Then God said, “Let there be lights in the firmament of the heavens to divide the day from the night; and let them be for signs and seasons, and for days and years; and let them be for lights in the firmament of the heavens to give light on the earth”; and it was so. Then God made two great lights: the greater light to rule the day, and the lesser light to rule the night. He made the stars also. God set them in the firmament of the heavens to give light on the earth, and to rule over the day and over the night, and to divide the light from the darkness. And God saw that it was good. So the evening and the morning were the fourth day (vv. 14–19).
On the seventh day of the creation week, we are introduced not only to the Sabbath, but also to the God-ordained weekly cycle of seven days. That a week is seven days in length was established at the beginning of creation. So, from Genesis 1–2 we get the foundational framework for marking time—days, weeks, seasons, and years.
Nothing God does is insignificant. Every aspect of His creation has a purpose, and time is no different. Not only does Genesis reveal where we came from—it is also where He begins to reveal the purpose of His creation and the span of time He has appointed for it. None of this was arbitrary. God didn’t rest on the seventh day because He was tired—He rested to create the Sabbath, which He created to point mankind to Him and to His plan (Mark 2:27; Hebrews 4:9; 2 Peter 3:8). To ensure that the message inherent in the Sabbath wasn’t forgotten, God gave instructions on how this sacred day was to be observed (Exodus 20:8–11).
The foundation for what we understand about God’s plan and His purpose for mankind is laid in the opening pages of Scripture. Other passages fill in additional details and build upon the lessons contained in the “history of the heavens and the earth when they were created” (Genesis 2:4).
Rebellion and Divergence
In Genesis 3, we’re told about mankind’s first sin. Satan deceived Eve, and the result was that Adam and Eve rebelled against God. Mankind has followed in their footsteps ever since, and our acts of rebellion drive a wedge between us and God. But the rest of Scripture reveals that this wedge will not be permanent—that God has a plan to reconcile mankind to Himself. The weekly Sabbath reminds us of this.
Instead of looking to God as the source of guidance and instruction in life, mankind has taken that prerogative for itself, and the fruit of that approach is abundantly clear. Under the sway of “the prince of the power of the air, the spirit who now works in the sons of disobedience” (Ephesians 2:2), the very foundation upon which society is built was laid in opposition to God. Every attempt has been made to obscure God and His plan from view—and to replace it with anything and everything else.
It is no surprise, then, that when we look at how time is marked we see a divergence between the pattern God laid out in Genesis and the pattern used in society around us. We see this in the most basic unit of measurement on the calendar—the day. Instead of recognizing that days begin at sunset, the world counts them as if they begin in the dead of night. This “contribution” to the common calendar came courtesy of the ancient Romans and was popularized by Julius Caesar when he established the Julian calendar. Prior to that, sunrise was a popular starting point for counting the day in Egypt and other cultures, particularly where forms of sun worship were practiced.
The basis for counting seasons and years as laid out in Genesis involved the use of both the sun and the moon. The Hebrew calendar follows this pattern, so it is known as a lunisolar calendar. Because it tracks time in conjunction with the phases of the moon for months and anchors itself to the solar year mathematically, the annual Holy Days have always fallen during their corresponding agricultural seasons. By contrast, the Julian/Gregorian calendar is a solar calendar—it relies exclusively on the earth’s revolution around the sun to maintain alignment with the agricultural seasons. So, whereas the months on the Hebrew calendar are synchronized with the phases of the moon, there is a disconnect between the moon and the months on the Gregorian calendar.
God told Moses that the month of Abib “shall be your beginning of months; it shall be the first month of the year to you” (Exodus 12:2). God ordained that the year would begin in the spring—in harmony with the agricultural seasons. By contrast, the Julian and Gregorian calendars begin the year in the dead of winter.
The Pope’s Calendar and Us
Ancient Rome shaped the modern world in many ways, such as government and administration, law, engineering, cultural integration, and language—and one of the most significant Roman influences was the Julian calendar. This revised Roman system standardized the way time was tracked across the Western world for more than 1,600 years and lives on even today (with a tweak in the leap-year rules) in the Gregorian calendar. Interestingly, although the Gregorian calendar is named after Pope Gregory XIII, his calendar was just a modification of what an earlier Roman Pontiff, Julius Caesar—who also held the title Pontifex Maximus—originally created.
So, what does the use of the Pope’s calendar mean for followers of Christ today? Looking forward to the fall of “Babylon the great” (Revelation 18:2) and the return of Jesus Christ, we take to heart the admonition we read in Revelation 18:4: “Come out of her, my people, lest you share in her sins, and lest you receive of her plagues.” We are called to be spiritually separate from this world and its many pagan systems.
Does this mean that we are never to use the Roman calendar? Not at all. Calendars simply mark time, letting us synchronize our schedules and keep track of events and milestones. Jesus Christ lived in a society governed by two different calendars, and so do we—the Hebrew calendar was relied on for the Sabbath and the Holy Days, while the Julian calendar governed civil matters such as taxes and administrative records.
However, our use of this calendar does not mean that we should celebrate it. By way of example, Americans celebrated 250 years of independence on July 4, 2026, but this milestone was not universally celebrated around the world; rather, it was celebrated by those who celebrate what the United States of America is and represents. Each country has its own significant milestones that are celebrated by those who are part of those cultures.
In the same way, January 1 represents a milestone—the establishment of the Roman system to govern time. Those who get caught up in that day’s festivities are celebrating what the Roman system is and represents—a world held captive by the prince of the power of the air. Let us all give thanks to God that we have a weekly reminder of a better world to come.