Battle of Lemo
The Battle of Lemo was fought during the Finnish War between Sweden and Russia on 19–20 June 1808 (Julian calendar 7–8 June).
Christmas
Although the month and date of Jesus' birth are unknown, by the early - to - mid fourth century the Western Christian Church had placed Christmas on December 25, a date that was later adopted in the East. Today, most Christians celebrate on December 25 in the Gregorian calendar, which has been adopted almost universally in the civil calendars used in countries throughout the world. However, some Eastern Christian Churches celebrate Christmas on December 25 of the older Julian calendar, which currently corresponds to January 7 in the Gregorian calendar, the day after the Western Christian Church celebrates the Epiphany. This is not a disagreement over the date of Christmas as such, but rather a preference of which calendar should be used to determine the day that is December 25. Moreover, for Christians, the belief that God came into the world in the form of man to atone for the sins of humanity, rather than the exact birth date, is considered to be the primary purpose in celebrating Christmas.
Zeller's congruence
Zeller's congruence is an algorithm devised by Christian Zeller to calculate the day of the week for any Julian or Gregorian calendar date. It can be considered to be based on the conversion between Julian day and the calendar date.
Gregorian calendar
The Gregorian calendar is the most widely used civil calendar in the world. It is named after Pope Gregory XIII, who introduced it in October 1582. The calendar spaces leap years to make the average year 365.2425 days long, approximating the 365.2422 day tropical year that is determined by the Earth's rotation around the Sun. The rule for leap years is as follows:
Holocene calendar
Conversion from Julian or Gregorian calendar years to the Human Era can be achieved by adding 10,000 to the AD/CE year. The present year, 2019, can be transformed into a Holocene year by adding the digit "1" before it, making it 12,019 HE.  Years BC/BCE are converted by subtracting the BC/BCE year number from 10,001.
Roman Republic
Caesar was now the primary figure of the Roman state, enforcing and entrenching his powers. His enemies feared that he had ambitions to become an autocratic ruler. Arguing that the Roman Republic was in danger, a group of senators hatched a conspiracy and assassinated Caesar at a meeting of the Senate in March 44 BC.  Mark Antony, Caesar's lieutenant, condemned Caesar's assassination, and war broke out between the two factions. Antony was denounced as a public enemy, and Caesar's adopted son and chosen heir, Gaius Octavianus, was entrusted with the command of the war against him. At the Battle of Mutina Mark Antony was defeated by the consuls Hirtius and Pansa, who were both killed.
Most Holy Name of the Blessed Virgin Mary
The Feast of the Most Holy Name of the Blessed Virgin Mary is an optional memorial celebrated in the liturgical calendar of the Catholic Church on 12 September. It has been a universal Roman Rite feast since 1684, when Pope Innocent XI included it in the General Roman Calendar to commemorate the victory at the Battle of Vienna in 1683. It was removed from the Church calendar in the liturgical reform following Vatican II but restored by Pope Saint John Paul II in 2002, along with the Feast of the Holy Name of Jesus.
Gregorian calendar
To unambiguously specify the date, dual dating or Old Style (O.S.) and New Style (N.S.) are sometimes used with dates. Dual dating uses two consecutive years because of differences in the starting date of the year, or includes both the Julian and Gregorian dates. Old Style and New Style (N.S.) indicate either whether the start of the Julian year has been adjusted to start on 1 January (N.S.) even though documents written at the time use a different start of year (O.S.), or whether a date conforms to the Julian calendar (O.S.) rather than the Gregorian (N.S.).
Winter
In the UK, meteorologists consider winter to be the three coldest months of December, January and February. In Scandinavia, winter in one tradition begins on 14 October and ends on the last day of February. In Russia, currently calendar winter starts on 1 December and lasts through to the end of February, though traditionally it was reckoned from the Christmas (25 December in Julian calendar, or 7 January in Gregorian) until the Annunciation (25 March in Julian). In many countries in the Southern Hemisphere, including Australia, New Zealand and South Africa, winter begins on 1 June and ends on 31 August. In Celtic nations such as Ireland (using the Irish calendar) and in Scandinavia, the winter solstice is traditionally considered as midwinter, with the winter season beginning 1 November, on All Hallows, or Samhain. Winter ends and spring begins on Imbolc, or Candlemas, which is 1 or 2 February. This system of seasons is based on the length of days exclusively. (The three - month period of the shortest days and weakest solar radiation occurs during November, December and January in the Northern Hemisphere and May, June and July in the Southern Hemisphere.)
Gregorian calendar
The Gregorian calendar was a reform of the Julian calendar instituted in 1582 by Pope Gregory XIII, after whom the calendar was named, by papal bull Inter gravissimas dated 24 February 1582. The motivation for the adjustment was to bring the date for the celebration of Easter to the time of year in which it was celebrated when it was introduced by the early Church. Although a recommendation of the First Council of Nicaea in 325 specified that all Christians should celebrate Easter on the same day, it took almost five centuries before virtually all Christians achieved that objective by adopting the rules of the Church of Alexandria (see Easter for the issues which arose).
Julian calendar
The Julian calendar, proposed by Julius Caesar in 708 AUC (46 BC/BCE), was a reform of the Roman calendar. It took effect on 1 January 709 AUC (45 BC/BCE), by edict. It was the predominant calendar in the Roman world, most of Europe, and in European settlements in the Americas and elsewhere, until it was gradually replaced by the Gregorian calendar, promulgated in 1582 by Pope Gregory XIII.
Gregorian calendar
Prior to 1917, Turkey used the lunar Islamic calendar with the Hegira era for general purposes and the Julian calendar for fiscal purposes. The start of the fiscal year was eventually fixed at 1 March and the year number was roughly equivalent to the Hegira year (see Rumi calendar). As the solar year is longer than the lunar year this originally entailed the use of "escape years" every so often when the number of the fiscal year would jump. From 1 March 1917 the fiscal year became Gregorian, rather than Julian. On 1 January 1926 the use of the Gregorian calendar was extended to include use for general purposes and the number of the year became the same as in other countries.
Gregorian calendar
In conjunction with the system of months there is a system of weeks. A physical or electronic calendar provides conversion from a given date to the weekday, and shows multiple dates for a given weekday and month. Calculating the day of the week is not very simple, because of the irregularities in the Gregorian system. When the Gregorian calendar was adopted by each country, the weekly cycle continued uninterrupted. For example, in the case of the few countries that adopted the reformed calendar on the date proposed by Gregory XIII for the calendar's adoption, Friday, 15 October 1582, the preceding date was Thursday, 4 October 1582 (Julian calendar).
Gregorian calendar
The Gregorian calendar is the most widely used civil calendar in the world. It is named after Pope Gregory XIII, who introduced it in October 1582. The calendar spaces leap years to make the average year 365.2425 days long, approximating the 365.2422 day tropical year that is determined by the Earth's revolution around the Sun. The rule for leap years is as follows:
Stefan Štiljanović
Stefan Štiljanović (; fl. 1498 – 1543) was the last prominent Serbian nobleman of the period of Ottoman subjugation of Serbia, and according to folklore, he was the last Despot of Serbia. He ruled a large territory under the Hungarian crown, due to his famed operations against the Ottoman Empire in the frontiers. Štiljanović is venerated as a Saint in the Serbian Orthodox Church on the 4 October (Julian Calendar) or 17 October (Gregorian Calendar) which comes to the same thing.
Computus
Computus (Latin for ``computation '') is a calculation that determines the calendar date of Easter. Because the date is based on a calendar - dependent equinox rather than the astronomical one, there are differences between calculations done according to the Julian calendar and the modern Gregorian calendar. The name has been used for this procedure since the early Middle Ages, as it was considered the most important computation of the age.
Battle of Wittstock
The Battle of Wittstock took place during the Thirty Years' War (1618-1648). It was fought on 24 September (Julian calendar) or 4 October (Gregorian calendar) 1636. A Swedish-allied army commanded jointly by Johan Banér and Alexander Leslie, later 1st Earl of Leven decisively defeated a combined Imperial-Saxon army, led by Count Melchior von Hatzfeld and the Saxon Elector John George I.
Gregorian calendar
The Gregorian calendar is a solar calendar. A regular Gregorian year consists of 365 days, but as in the Julian calendar, in a leap year, a leap day is added to February. In the Julian calendar a leap year occurs every 4 years, but the Gregorian calendar omits 3 leap days every 400 years. In the Julian calendar, this leap day was inserted by doubling 24 February, and the Gregorian reform did not change the date of the leap day. In the modern period, it has become customary to number the days from the beginning of the month, and February 29th is often considered as the leap day. Some churches, notably the Roman Catholic Church, delay February festivals after the 23rd by one day in leap years.
Julian year (astronomy)
A Julian year should not be confused with the Julian day (also Julian day number or JDN), which is also used in astronomy.  Despite the similarity of names, there is little connection between the two. It is a way of expressing a date as the integer number of days that have elapsed since a reference date or initial epoch. The Julian day uniquely specifies a date without reference to its day, month, or year in any particular calendar. A specific time within a day is specified via a decimal fraction.
History of calendars
The Gregorian calendar was introduced as a refinement of the Julian calendar in 1582, and is today in worldwide use as the de facto calendar for secular purposes.
When did the person who the Julian calendar is named for die?
The Julian calendar was named for whom?
Julius Caesar
When did #1 die?
March 44 BC