According to a contemporary historian, Giovanni Baglione, between palaces, castles, churches and convents, Peparelli participated in about seventy construction projects but only about thirty can be attributed to him with certainty.
[1] In 1601 he was apprenticed to the architect Ottaviano Nonni and with him, contributed to the design of Santa Maria in Traspontina.
[2] He was skilled in engineering, cartography and hydraulics; and he was often commissioned with the construction of buildings designed by other architects.
Peparelli often worked in various capacities with Girolamo Rainaldi,[3] such as the Chiesa di S. Teresa in Caprarola.
Around 1630 Pope Urban VIII decided to rebuild the church of San Caio from the ground up and retained Peparelli and Vincenzo della Greca as architects; the works lasted from 1630 to 1631.