In this article the author underlines the deep link beetwen mathematics and theology in Cusanus’ philosophical system and analyzes the meaning and the limits of Cusanus’ mathematical proceeding. She points out the mathematical works in wich the Cardinal tries to solve the vexata quaestio of the “squaring of the circle” through the method (ars) of the coincidence. All his attempts ended in failure, but, in a bid to realise the coveted mathematica perfectio (i.e. the squaring of the circle), Cusano, dispite the evident inadequacy of metric criteria of his proceeding, makes a significant contribution to the modern scientific forma mentis, in particular in regard to his ideas of mens as mensura, of the Infinite and of the space.

Key-words: Mathematics; Squaring of the Circle; Coincidentia