The ancient Greeks and Romans used many systems to designate and keep track of years. This was important for maintaining a chronology that marked events in their histories and enabled them to determine the number of years that elapsed between events. The system of numbering years and designating them A.D. or B.C. did not begin until long after the ancient period.
The most common way that the Greeks and Romans kept track of years was to associate each year with the name of a person, usually someone of great importance. The early Greeks, for example, designated years by the names of the archons* of Athens. After the 300s B.C., many Greek historians used a system based on the names of winners at the Olympic Games. The Romans used the names of consuls* and emperors. In a system such as this, lists of the years with their names had to be carefully maintained and passed down over centuries; otherwise, the designations would lose their meaning.
The Greeks and Romans also kept track of years with a system based on eras—periods of time in which a succession of years is numbered from a certain starting date, often an important political, military, or religious event. One era widely used in Greece was the Seleucid era, based on the ruling years of the Seleucid dynasty. Another era used by the Greeks was that of the Trojan War (usually given as 1183/82 B.C.) The early Romans dated events from the founding of Rome (753 B.C.). The AUC system of recording Roman history uses this date. (The abbreviation AUC comes from the Latin ab urbe condita, “from the year of the founding of the city.”) During the empire, the Romans often used eras based on the reigns of their emperors.
Calendars, systems for measuring and recording the passage of time, were another system of timekeeping. Calendars had been used by the ancient Babylonians and the Egyptians before the Greeks and Romans. In 46 B.C. Julius Caesar instituted a revision of the Roman calendar that made it more in keeping with the seasons of the year. The Julian calendar, as it came to be known, gradually came to dominate most official timekeeping practices in the Mediterranean region for the next 1,500 years. (See also Astronomy and Astrology; Festivals and Feasts, Greek; Festivals and Feasts, Roman.)
* archon in ancient Greece, the highest office of state
* consul one of two chief governmental officials of Rome, chosen annually and serving for a year