The terms anno Domini (AD) and before Christ (BC) are used when designating years in the Gregorian and Julian calendars. The term anno Domini is Medieval Latin and means "in the year of the Lord" but is often presented using "our Lord" instead of "the Lord", taken from the full original phrase "anno Domini nostri Jesu Christi", which translates to "in the year of our Lord Jesus Christ". The form "BC" is specific to English, and equivalent abbreviations are used in other languages: the Latin form, rarely used in English, is ante Christum natum (ACN) or ante Christum (AC).
Year 800 (DCCC) was a leap year starting on Wednesday of the Julian calendar, the 800th year of the Common Era (CE) and Anno Domini (AD) designations, the 800th year of the 1st millennium, the 100th and last year of the 8th century, and the 1st year of the 800s decade. It was around this time that the Anno Domini calendar era became the prevalent method in Europe for naming years, so from this time on, the years began to be known as 800 and onwards.
AD 1 (I) or 1 CE was a common year starting on Saturday or Sunday, a common year starting on Saturday by the proleptic Julian calendar, and a common year starting on Monday by the proleptic Gregorian calendar. It is the epoch year for the Anno Domini (AD) Christian calendar era, and the 1st year of the 1st century and 1st millennium of the Christian or Common Era (CE).
AD 4 was a common year starting on Wednesday or a leap year starting on Tuesday of the Julian calendar and a leap year starting on Tuesday of the Proleptic Julian calendar. In the Roman Empire, it was known as the Year of the Consulship of Catus and Saturninus. The denomination "AD 4" for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years.
AD 64 (LXIV) was a leap year starting on Sunday of the Julian calendar, the 64th Year of the Anno Domini designation, the 64th year of the 1st millennium, the 64th year of the 1st century, and the 4th year of the 7th decade. At the time, it was known as the Year of the Consulship of Bassus and Crassus. The denomination AD 64 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years.
AD 95 (XCV) was a common year starting on Thursday of the Julian calendar, the 95th Year of the Anno Domini (AD) designation, the 95th year of the 1st millennium, the 95th year of the end of the 1st century, and the 5th year of the 10th decade. In the Roman Empire, it was known as the Year of the Consulship of Augustus and Clemens. The denomination AD 95 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years.
100 (C) was a leap year starting on Wednesday of the Julian calendar, the 100th year of the Common Era (CE) and Anno Domini (AD) designations, the 100th year of the 1st millennium, the 100th and last year of the 1st century, and the 1st year of the 100s decade. As of the start of 100, the Gregorian calendar was 2 days behind the Julian calendar, which was the dominant calendar of the time.
Year 104 (CIV) was a leap year starting on Monday of the Julian calendar, the 104th Year of the Anno Domini (AD) designation, the 104th year of the 1st millennium, the 4th year of the 2nd century, and the 5th year of the 100s decade. At the time, it was known as the Year of the Consulship of Suburanus and Marcellus. The denomination 104 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years.
Year 136 (CXXXVI) was a leap year starting on Saturday of the Julian calendar, the 136th Year of the Common Era (CE) and Anno Domini (AD) designations, the 136th year of the 1st millennium, the 36th year of the 2nd century, and the 7th year of the 130s decade. At the time, it was known as the Year of the Consulship of Commodus and Civica. The denomination 136 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years.
Year 780 (DCCLXXX) was a leap year starting on Saturday of the Julian calendar, the 780th year of the Common Era (CE) and Anno Domini (AD) designations, the 780th year of the 1st millennium, the 80th year of the 8th century, and the 1st year of the 780s decade. The denomination 780 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years.
Year 14 BC was either a common year starting on Thursday or Friday or a leap year starting on Wednesday, Thursday or Friday of the Julian calendar and a common year starting on Tuesday of the Proleptic Julian calendar. At the time, it was known as the Year of the Consulship of Crassus and Lentulus. The denomination 14 BC for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years.
Year 398 (CCCXCVIII) was a common year starting on Friday of the Julian calendar, the 395th Year of the Common Era (CE) and Anno Domini (AD) designations, the 398th year of the 1st millennium, the last 3 years of the 4th century, and the 9th and pre-final year of the 390s decade. At the time, it was known as the Year of the Consulship of Augustus and Eutychianus. The denomination 398 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years.
Year 610 (DCX) was a common year starting on Thursday of the Julian calendar, the 610th year of the Common Era (CE) and Anno Domini (AD) designations, the 610th year of the 1st millennium, the 10th year of the 7th century, and the 1st year of the 610s decade. The denomination 610 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years.
The proleptic Julian calendar is produced by extending the Julian calendar backwards to dates preceding AD 8 when the quadrennial leap year stabilized. The leap years that were actually observed between the implementation of the Julian calendar in 45 BC and AD 8 were erratic.
Year 246 (CCXLVI) was a common year starting on Thursday of the Julian calendar, the 246th Year of the Common Era (CE) and Anno Domini (AD) designations, the 246th year of the 1st millennium, the 46th year of the 3rd century, and the 7th year of the 240s decade. At the time, it was known as the Year of the Consulship of Praesens and Albinus. The denomination 246 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years.
Year 295 (CCXCV) was a common year starting on Tuesday of the Julian calendar, the 295th Year of the Common Era (CE) and Anno Domini (AD) designations, the 295th year of the 1st millennium, the 95th year and last 6 years of the 3rd century, and the 6th year of the 290s decade. At the time, it was known as the Year of the Consulship of Tuscus and Anullinus. The denomination 295 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years.
Year 1 BC was a common year starting on Friday or Saturday in the Julian calendar and a leap year starting on Thursday in the proleptic Julian calendar. It was also a leap year starting on Saturday in the Proleptic Gregorian calendar. At the time, it was known as the Year of the Consulship of Lentulus and Piso. The denomination 1 BC for this year has been used since the early medieval period when the Anno Domini calendar era became the prevalent method in Europe for naming years. The following year is AD 1 in the widely used Julian calendar and the proleptic Gregorian calendar, which both do not have a "year zero".
A calendar era is the period of time elapsed since one epoch of a calendar and, if it exists, before the next one. For example, the current year is numbered 2025 in the Gregorian calendar, which numbers its years in the Western Christian era.
The Era of the Martyrs, also known as the Diocletian era, is a method of numbering years based on the reign of Roman Emperor Diocletian who instigated the last major persecution against Christians in the Empire. It was used by the Church of Alexandria beginning in the 4th century AD and it has been used by the Coptic Orthodox Church of Alexandria from the 5th century until the present. This era was used to number the year in Easter tables produced by the Church of Alexandria.
A year zero does not exist in the Anno Domini (AD) calendar year system commonly used to number years in the Gregorian calendar ; in this system, the year 1 BC is followed directly by year AD 1. However, there is a year zero in both the astronomical year numbering system, and the ISO 8601:2004 system, a data interchange standard for certain time and calendar information. There is also a year zero in most Buddhist and Hindu calendars.
