Kirik's treatise on chronology: Novgorod, XIIth Century A Novgorodian monk, Kirik, composed in year 6644 (1136) a Treatise on calendar computations which gained him the title of 'First Russian mathematician'. An edition of the Treatise and French translations of this Treatise and of an associated short Chronology are given and discussed. Greek and Slavonic influences are present. Interesting mathematical contributions may be seen in the numerical notations and in the calculation of big numbers, on the basis of the date 6644. This date has a symbolic meaning, as Novgorod acquired in this year the right to choose its prince. A chapter on successive divisions of the hour by five, creating very small units of time, raises many questions. Kirik participated probably in the redaction of a Questionnary on everyday religious problems, thus assassing a wide interest in the life of his city.