In 1467 emissaries of pope Paul the second came here to arrest a group of people, men and women, accused of heresy. Since about 1300 the sect of the fraticelli, the friars of the poor life, condemned more than once by the Church, had spread at Poli, and it had won many followers, including the Conti who governed the fief; the meetings were held secretly in scattered places, at Casape and elsewhere. The pope first exhorted them to renounce their practices, then had them seized by force and tried. The chief accused was baron Stefano Conti, guilty of having favoured the growth of the sect on his lands: he was imprisoned in Castel Sant'Angelo and forced to give up the fief in favour of his sons. With the people the pope was milder, but not briefer: he laid on the whole village an annual penance, a procession on the first day of Lent and a meal for twelve of the local poor. That penance was revoked in 1886, more than four centuries after it had been imposed.
On the thirteenth of May 1655, in the frescoed wing of the main floor of Palazzo Conti, Michelangelo Conti was born, who would become pope under the name of Innocent the thirteenth. His family had held Poli for six centuries, having wrested it from the Oddoni around 1200, and today part of the palace houses the town hall while the main floor has stayed with the Conti. The village goes back to 992 and belonged first to a Benedictine monastery in Rome, then, from 1081, to the abbey of San Paolo fuori le mura, by a donation willed by Gregory the seventh. It has stayed as it was: thirty-five very narrow alleys opening off a single long street, like the bones of a fish. Above it stands the rock of Guadagnolo, which shared its fate for some eight hundred years and left the same comune only in 1930, and which since 2010 can be reached from here by road. And four men of Poli were shot at the Fosse Ardeatine, in March 1944.