Gregory XV, born Alessandro Ludovisi, was elected Pope in a conclave held on February 9, 1621, marking a pivotal moment in papal history as he became the last pope to be elected by acclamation. After the death of Pope Paul V, the cardinal electors convened in Rome to discuss the future leadership of the Catholic Church. Acclamation, a practice where a candidate is chosen through public consensus rather than a formal vote, was a method increasingly seen as outdated by this time. Nevertheless, the cardinals quickly rallied around Gregory, identifying him as a suitable candidate due to his earlier diplomatic and administrative efforts in the church. His election was finalized in a mere three days, showcasing the urgency in selecting a new leader amidst the church's challenges during the early 17th century.Gregory XV took significant steps during his papacy, which lasted until his death in 1623. His most notable contributions included the posthumous canonization of several saints and active involvement in missionary work, particularly in the New World and Asia. He also enacted reforms in the administration of church properties and funds, along with regulating clergy conduct. These actions reinforced papal authority and showcased the Catholic Church's intentions to revitalize its influence during a time of Protestant Reformation and internal challenges. He was also instrumental in promoting the cause of the canonization of saints, including Ignatius of Loyola.This election marks a historical turning point, as subsequent popes would be elected through a more structured voting process. After Gregory XV, the style of conclave would evolve, thereby diminishing the prominence of acclamation and signaling changing dynamics within the church hierarchy and governance. His legacy includes being the catalyst for these procedural changes that would define future papal elections.