The history of time measurement runs together with man’s evolution and all his activities, religious, social, political and scientific which have required a more exact and less arbitrary measurement: the notion of time follows the demand of measuring its flowing. The Sundial allows such measurement through the position and the length of the shade of a stick (gnomon). Another way of measuring time is through a mechanical clock, which has the merit to be autonomous by means of its own strength engine. Through the XI and XII century the first mechanical clocks were developed for monastic use with the purpose of establishing the time of prayer and regulating monastic life. From the early XIV century all the rich cities were equipped with a great clock, symbol of power and prosperity. These clocks could be installed on top of the bell towers or could become real tower architectures. The clock tower in all cities, either Venice or Brescia , measured both religious and working time. In Brescia, in St. Joseph’s cloisters, an important complex near the monumental Clock Tower of piazza della Loggia both forms of measurement, the sundial and the mechanical clocks, are present. Our research focuses on the study of such forms and their mutual interaction , and it will be developed into two essays, that will underline, through an architectural relief, the characteristics of such tool (Renato Marmori’s essay) and the connection of the sundial with the other clocks in St. Joseph’s Church and those located in the different cloisters (Massimo De Paoli’s), clocks which are fixed by a midday measured by the same sundial.