Kirik Novgorodets was the monk and the regent of church chorus in a monastery founded by St. Anthony of Rome in Novgorod the Great, later he was a deacon, the priest and the important person in retinue of Nifont, the archbishop of Novgorod the Great. Kirik Novgorodets was born in 1110 and he has died after 1156/58. We know two compositions of Kirik: it is "The Questions of Kirik" (“Вопрошания Кирика, иже вопроси епископа Нифонта и инех”) and "Manual about numbers" («Кирика диакона и доместика новгородского Антоньева монастыря учение им же ведати человеку числа всех лет»). "The Questions" are devoted discussion of difficult situations in practice of the Novgorod orthodox church; some centuries this text was a component of the orthodox initial right. In this text of Kirik we can see the information on a daily life of Novgorodians. For example, in this text the Novgorod birch bark manuscripts are mentioned (they have been found by archeologists only in 1951). However for history of science "Manual about numbers" is more interesting. In this text Kirik calculated quantity of months, weeks, days and hours which have passed from Creation of the World. He shows ability to make arithmetic operations with very big numbers; probably, he was the author of special designations for such numbers. Also Kirik specifies the least particle of time (about 0.04608 seconds); this value can be received only as a result of experiment. Really, there is a minimum particle of time distinguishable by person and possible in a piece of music. (Similar division of time in the Western Europe and in Byzantium was more inexact.) Thus Kirik used equinoctial hours, it was atypical in the Middle Ages: during this period day or night hour was equaled the one twelfth part of light or dark time of day. Besides, Kirik has offered idea about renewal of four elements of Nature and about periodicity of these renewals; similar ideas were unknown in the Western Europe. Also in compositions of Kirik it is possible to see interest to astrology. In Novgorod the Great the majority of people were able to read and write; in 1030 there Grand Prince Yaroslav the Wise has founded school for teaching to the bookness (книжность). The city had numerous connections with the East and West countries, monasteries and rich people owned the big libraries. Kirik Novgorodets has read many western and Byzantian books. He knew mathematics, astronomy, history, theology, philosophy, music and, probably, medicine.