Calendar [календар]. A system of measuring time based on the periodicity of certain natural processes. Very little is known about the Ukrainian calendar in prehistoric times, but the popular names of the months indicate that some kind of calendar was used (see Folk calendar).

Along with Christianity (see Christianization of Ukraine), Kyivan Rus’ adopted from Byzantium the Byzantine form of the calendar introduced by Julius Caesar in 46 BC (known as the Julian calendar). According to this calendar the average length of the year is 365 days and 6 hours. This exceeds the real solar year by 11 minutes and 14 seconds; hence, over time, the Julian calendar diverges more and more from the solar year (15.45 days by 1980). Pope Gregory XIII reformed the calendar in 1582, and since then the Gregorian calendar has been officially recognized by the Catholic church and Catholic countries. Protestants adopted it in the 18th century.

Poland adopted the Gregorian calendar in 1583, but King Stephen Báthory, by the edicts of 1584, 1585, and 1586, permitted the Orthodox church to keep the Julian calendar. Orthodox leaders (Herasym Smotrytsky, V. Surazky, Stepan Zyzanii, and others) rejected the new calendar on dogmatic and ritualistic grounds. The Ukrainians who accepted the union with Rome (see Church Union of Berestia) also kept the old calendar, in spite of attempts, mainly in the 17th century, to have them adopt the Gregorian calendar. After the partition of Poland the Russian government reintroduced the Julian calendar in those areas of civil life where the Polish authorities had instituted the Gregorian calendar. Meanwhile, Austria's efforts to introduce the new calendar among the Ukrainians of Galicia in 1773, 1798, and 1812 proved fruitless.

The new calendar was introduced into civil life by the Ukrainian Central Rada on 1 March 1918, while the Julian calendar continues to be used in the church to this day. Attempts to institute the Gregorian calendar in 1917–18 in the Ukrainian Catholic Stanyslaviv eparchy under Bishop Hryhorii Khomyshyn and in the 1930s in the Orthodox church in Poland were strongly opposed by the Ukrainian community and did not succeed. However, the new calendar was adopted by some Ukrainian church communities outside Ukraine, notably by the Ukrainian Catholic church in Argentina, Brazil, and some eparchies in the USA and Canada.

 The two calendars differ not only on the fixed feasts, but also on the movable feasts of the Easter cycle. The dates of the latter are calculated according to the paschal period, which is based on the monthly cycle. The Eastern church uses the period introduced by Dionysius Exiguus in 525. This has been modified by the Western church as well.

In Kyivan Rus’ the years were numbered from the creation of the world; hence, old Ukrainian documents are usually dated in this way. In the 14th century documents began to be dated from the birth of Christ as well, the difference between the two systems of dating being 5,508 years. The calendar year in civil life began on 1 March and in church life on 1 September, as in Byzantium since the time of Justinian I. This difference led to confusion in the dating of the various entries in the chronicles. Only by the end of the 15th century was 1 September accepted as the beginning of both the civil and the church year. In 1700 Peter I introduced the Western practice of starting the year with 1 January. In the church, however, the older practice is still observed. At the same time Peter established in Ukraine the numeration of years from Christ's birth.

Viktor Pavlovsky

[This article originally appeared in the Encyclopedia of Ukraine, vol. 1 (1984).]