Following Pope Urban II’s famous call to reclaim the Holy Land at the Council of Clermont in 1095, Peter took to the countryside. Riding from village to village on a donkey, his fiery, apocalyptic preaching quickly ignited the People's Crusade (or the Crusade of the Poor).

Unlike the official armies of armored knights organized by European nobility, Peter gathered a massive, undisciplined force estimated at 20,000 to 40,000 people largely composed of impoverished peasants, women, and children.

As Peter’s unruly army marched across Europe toward Constantinople, parts of his faction, alongside other crusader bands, engaged in brutal, unprovoked pogroms against Jewish communities in cities like Cologne, Mainz, and Worms.

On October 21, 1096, they were completely decimated at the Battle of Civetot. Peter survived only because he had temporarily returned to Constantinople to secure supplies.

The Crusader army faced extreme famine, disease, and heavy casualties while besieging the city of Antioch, leading widespread desperation and desertions across the ranks

As a prominent spiritual leader of the Crusade who had previously led the People's Crusade, Peter himself slipped out of the camp to try to escape the misery.

Peter was caught and brought back to the camp—famously by Tancred or under orders from the crusader leadership—which severely damaged his initial glowing reputation among the chroniclers and troops. Though he would later be redeemed and continues to serve the latin forces untip their capture of Jerusalem in 1099