Early medieval arithmetic; subject of arithmetic; definitions of number; philosophy of number; Augustine; Boethius

The paper deals with early medieval mathematics (mainly arithmetic) and presents mathematical knowledge as an important tool for human way to God's wisdom. The aim of this paper is focused on the definitions of the subject of arithmetic in early medieval texts created between the late 4th and early 7th century. The aim is to highlight the fact that the traditional definitions of a number (i.e., the subject of arithmetic) correspond with appropriate topics which exist within arithmetic. If a number is characterised as a discrete quantity, it reflects the classification and typological surveys of the mathematical properties of numbers. If a number is defined as a collection of units, this definition refers to the issue of figural numbers, whereas if the number is marked as the quantity that emerges and then returns to the unit, it is possible to detect the themes of numerical sequences and ratios, including their transfers.