Editing Primary Chronicle (section)

==== Opening date error ====
The historical period covered in the ''Tale of Bygone Years'' begins with [[biblical times]], in the introductory portion of the text, and concludes with the year 1117 in the chronicle's third edition. Russian philologist [[Aleksey Shakhmatov]] was the first one to discover early on that the chronology of the ''Primary Chronicle'' opens with an error. The ''Laurentian'' text of the ''Chronicle'' says: "In the year 6360 (852), the fifteenth of the indiction, at the accession of the Emperor Michael, the land of Rus' was first named".{{sfn|Cross|Sherbowitz-Wetzor|1953|pp=24, 58}} It is thus claimed that the reign of Byzantine emperor [[Michael III]] began in this year, but Byzantine sources (such as 11th-century Greek historian [[John Skylitzes]]' account<ref>{{cite book | last1=Skylitzes|  first1=John | translator-last=Wortley | translator-first=John |title=John Skylitzes: A Synopsis of Byzantine History, 811–1057: Translation and Notes | doi=10.1017/CBO9780511779657 | isbn=9780511779657 | publisher=Cambridge University Press | location=Cambridge, MA | year=2010}}</ref> ) point out that it began on 21 January 842.{{sfn|Cross|Sherbowitz-Wetzor|1953|p=30}}{{sfn|Ostrowski|2018|p=44}} Shakhmatov (1897) demonstrated that an editor based himself on a miscalculation found in the ''Short History'' of [[Nikephoros I of Constantinople]].{{sfn|Cross|Sherbowitz-Wetzor|1953|p=30}}{{sfn|Ostrowski|2018|p=44}} Moreover, a few sentences later, the text states: 'from the birth of Christ to Constantine, 318 years; and from Constantine to Michael, 542 years. Twenty-nine years passed between the first year of Michael's reign and the accession of Oleg, Prince of Rus'.'{{sfn|Cross|Sherbowitz-Wetzor|1953|p=58–59}}{{sfn|Ostrowski|2018|p=44}} However, [[Constantine the Great]] acceded in 313, not 318, and the resulting sum of 318+542 years leads to another erroneous accession of Michael III, this time in 860.{{sfn|Cross|Sherbowitz-Wetzor|1953|p=30}}{{sfn|Ostrowski|2018|p=44}} This then leads to an internal contradiction, when "Michael the Emperor" is said to have mounted a campaign against the Bulgars in 853–858 (6361–6366),{{sfn|Cross|Sherbowitz-Wetzor|1953|p=59}} which could not have happened before he became Byzantine emperor in 860 according to the latter accession date.{{sfn|Ostrowski|2018|p=44}}