View source for Indiction

{{short description|Any of the years in a 15-year cycle used to date medieval documents throughout Europe}}
{{inline|date=April 2020}}
{{distinguish|indictment}}
An '''indiction''' ({{langx|la|indictio}}, impost) was a periodic reassessment of taxation in the [[Roman Empire]] which took place every fifteen years. In [[Late Antiquity]], this 15-year cycle began to be used to date documents and it continued to be used for this purpose in [[Medieval]] Europe,<ref>{{Cite web|title=indiction|url=https://www.merriam-webster.com/dictionary/indiction|access-date=2020-08-07|website=www.merriam-webster.com|language=en|archive-date=2021-04-20|archive-url=https://web.archive.org/web/20210420103912/https://www.merriam-webster.com/dictionary/indiction|url-status=live}}</ref> and can also refer to an individual year in the cycle; for example, "the fourth indiction" came to mean the fourth year of the current indiction. Since the cycles themselves were not numbered, other information is needed to identify the specific year.

==History==
Indictions originally referred to the periodic reassessment for an agricultural or land tax in the [[Roman Empire]]. There were three different cycles: a 15-year cycle used throughout the empire; a 14-year cycle used in [[Roman Egypt]]; and a five year cycle called the ''[[lustrum]]'', derived from the [[Roman Republic]]an census. Changes to the tax system usually took place at the beginning of one of these cycles and at the end of the indiction [[Roman emperor|Emperors]] often chose to forgive any [[arrears]]. The 15-year cycle can be traced in literary and epigraphic references to taxation reforms and the cancellation of arrears.<ref> Duncan-Jones 1994 pp.59-63.</ref>

===Principate===
The ''[[Chronicon Paschale]]'' (c. 630 AD) claims that the 15-year cycle was instituted by [[Julius Caesar]] in 49 BC, which was also the first year of the Antiochene era, but there is no other evidence for this and, if the cycle were the same one known from later periods, the start date ought to be 48 BC.<ref>Duncan-Jones 1994 p 59 n. 66.</ref> The earliest known event associated with the 15-year cycle is the establishment of a special board of three [[praetor]]s to pursue arrears for the cycle ending in 42 AD, under [[Claudius]].<ref>[[Cassius Dio]], ''Roman History'' 60.10.4</ref><ref name="DJ60">Duncan-Jones 1994 p. 60</ref> The beginning of the cycle in 58 AD coincides with a set of tax reforms and remissions instituted by [[Nero]].<ref>[[Tacitus]], ''Annales'' 13.31, 50-51</ref><ref name="DJ60"/> [[Vespasian]] carried out a census of Italy at the start of the next indiction in 73 AD<ref>''[[Prosopographia Imperii Romani|PIR]]''<sup>2</sup> 3, p. 182</ref><ref name="DJ60"/> The indiction starting in 103 AD may coincide with the tax remission by [[Trajan]] depicted on the [[Plutei of Trajan]].<ref name="DJ60"/> At the start of the next indiction in 118 AD, [[Hadrian]] wrote off 900,000,000 [[sesterces]] of tax arrears, which he refers to in an inscription as the largest remission ever granted.<ref>''[[Inscriptiones Latinae Selectae|ILS]]'' 309; Cassius Dio 69.8.1; ''[[Historia Augusta]] Hadriani'' 7.6</ref><ref name="DJ60"/> He again remitted arrears at the start of the next indiction in AD 133,<ref>Cassius Dio 71.32.2</ref><ref name="DJ60"/> as did [[Antoninus Pius]] at the start of the next indiction in 148 AD.<ref>''Chronicon Paschale'' (''Chron. Min.'' I, p. 224)</ref><ref name="DJ60"/> [[Marcus Aurelius]] and [[Commodus]] carried out another remission at the start of the indiction beginning in 178 AD.<ref>Cassius Dio 71.32.2; [[Chronograph of 354]] (''Chron. Min.'' I, p. 147)</ref><ref name="DJ60"/> 

The 14-year cycle used in Egypt derived from the fact that liability for the Egyptian [[poll tax]] began at the age of fourteen, necessitating a new survey of the population every fourteen years. Tax reforms and remissions recorded in [[papyrus]] sources indicate that it was also in existence in the first century AD.<ref name=DJ61>Duncan-Jones 1994 p. 61.</ref> The first evidence is an edict by [[Marcus Mettius Rufus]], the [[Prefect of Egypt]] in AD 89, requiring property and loans to be registered.<ref>[[Papyrus Oxyrhynchus]] 237, col. 8 lines 27-43. English translation in [[A. S. Hunt]] and C.C. Edgar, ''Select Papyri, II. Non-literary Papyri. Public Documents'' (London: Loeb, 1932), pp.&nbsp;104-109 no.&nbsp;219</ref><ref name=DJ61/> The next cycle in 103 AD coincides with reforms to record-keeping.<ref>''SB'' 7378; English translation in Hunt and Edgar, ''Select Papyri, II'', pp. 574-577</ref><ref name=DJ61/> The beginning of the cycle in 117 AD coincided with the 15-year cycle and was the occasion of Hadrian's large tax remission.<ref name=DJ61/> This 14-year cycle is last attested in 257 AD.<ref>Duncan-Jones 1994 p. 62 n. 84.</ref> From 287 AD, at the latest, Roman Egypt used a system of 5-year cycles, then a non-cyclic series which reached number 26 by 318 AD.<ref>Duncan-Jones 1994 pp. 62-63.</ref>

===Late Antiquity and Middle Ages===
The 15-year cycle was introduced as a dating system on documents throughout the Roman empire by [[Constantine the Great|Constantine]] in 312 AD and it was in used in Egypt by 314 AD.<ref>Duncan-Jones 1994 p.&nbsp;63.</ref> The ''[[Chronicon Paschale]]'' (c. 630 AD) assigned its first year to 312–313 AD, whereas a [[Coptic Orthodox Church of Alexandria|Coptic]] document of 933 AD assigned its first year to 297–298 AD, one cycle earlier. Both of these were years of the [[Alexandrian calendar]] whose first day was [[Thout|Thoth]]&nbsp;1 on August 29 in years preceding common [[Julian calendar|Julian years]] and August 30 in years preceding leap years, hence each straddled two Julian years. The reason for beginning the year at that time was that the harvest would be in, and so it was an appropriate moment to calculate the taxes that should be paid.

The indiction was first used to date documents unrelated to tax collection in the mid-fourth century. By the late fourth century it was being used to date documents throughout the [[Mediterranean]]. In the [[Eastern Roman Empire]] outside of Egypt, the first day of its year was September 23, the birthday of [[Augustus]]. During the last half of the fifth century, probably 462 AD, this shifted to September 1, where it remained throughout the rest of the [[Byzantine Empire]]. In 537 AD, [[Justinian]] decreed that all dates must include the indiction via {{nowrap|Novella 47}},<ref>Constitutiones 4.21: De fide instrumentorum et amissione eorum et antapochis faciendis et de his quae sine scriptura fieri possunt; Novellae 47, 73.</ref> which eventually caused the Byzantine year to begin on {{nowrap|September 1}}.{{Clarify|date=April 2024|reason=How the primary source is relevant is not made clear - additional sources may be helpful?}} But in the western Mediterranean, its first day was {{nowrap|September 24}} according to [[Bede]], or the following {{nowrap|December 25}} or {{nowrap|January 1}}, called the papal indiction. An ''indictio Senensis'' beginning {{nowrap|September 8}} is sometimes mentioned.

The 7,980-year [[Julian Period#History|Julian Period]] was formed by multiplying the 15-year indiction cycle, the 28-year [[solar cycle (calendar)|solar cycle]] and the 19-year [[Metonic cycle]].

==Terminology==
When the term "indiction" began to be used, it referred only to the full cycle, and individual years were referred to as being Year 1 of the indiction, Year 2 of the indiction, etc. It gradually became common to apply the term to the years themselves, which thus became the first indiction, the second indiction, and so on.

==Calculation==
A useful chart providing all the equivalents can be found in Chaîne's book on chronology,<ref>Chaîne, Marius. 1925. ''La chronologie des temps chrétiens de l’Égypte et de l’Éthiopie''. Paris: Librairie Orientaliste Paul Geuthner.</ref> and can easily be consulted online at the Internet Archive, from [[iarchive:lachronologiedes0000chan/page/134/mode/2up|page 134]] to [[iarchive:lachronologiedes0000chan/page/172/mode/2up|page 172]]. 

The Roman indiction for a modern [[Anno Domini]] year ''Y'' (January 1 to December 31) may be calculated as follows:<ref>Blackburn & Holford-Strevens p. 771</ref>
:(''Y'' + 3) [[Modular arithmetic|mod]] 15

For example, the indiction for the year 2017 is 10:<ref>"Calendars" p. B4</ref>
:(2017 + 3) mod 15 = 10

However, this formula will produce an error for the last year of an indiction, where the modulo value is 0 instead of the expected 15, as can be seen when applying it to the year 2022:

:(2022+3) mod 15 = 0

One can simply read 0 as 15, but in order to have the correct result directly, the addition of a value of 1 from the offset may be delayed until after the '''mod''' operation:
:(''Y'' + 2) mod 15 + 1

That yields the expected answer, for 2022 again:
:(2022+2) mod 15 + 1 = 15

==References==
{{Reflist|30em}}
{{Wiktionary|indiction}}

==Works cited==
*Bonnie Blackburn, Leofranc Holford-Strevens, ''The Oxford Companion to the year'' (Oxford, 1999), p. 769-71.
*"Calendars" in ''Astronomical Almanac for the Year 2017'' (Washington: US Government Publishing Office, 2016) p. B4.
*''Chronicon paschale 284–628 AD'', trans. Michael Whitby, Mary Whitby (Liverpool, 1989), p. 10.
*Richard Duncan-Jones, ''Money and government in the Roman empire'' (Cambridge University Press, 1994) p. 59-63.

==Further reading==
*Roger S. Bagnall, [[Klaas Worp|K. A. Worp]], ''The chronological systems of Byzantine Egypt'' (Zutphen, 1978).
*Leo Depuydt, "AD 297 as the beginning of the first indiction cycle", ''The Bulletin of the American Society of Papyrologists, ''24:137&ndash;9.
*Yiannis E. Meimaris, ''Chronological systems in Roman-Byzantine Palestine and Arabia'' (Athens, 1992), 32-34
*S. P. Scott [Justinian I], "Forty-seventh new constitution" [Novella 47], ''The civil law'' [[Corpus Juris Civilis|[Corpvs jvris civilis]]] (1932; reprinted New York, 1973), '''16''' (in '''7'''): 213-15.

==External links==
*[http://www.newadvent.org/cathen/04636c.htm Dates and dating]
*A [http://www.skypoint.com/members/waltzmn/MSDating.html#Indiction chart of years and their indictions]

[[Category:Units of time]]
[[Category:Byzantine calendar]]
[[Category:Julian calendar]]