Final answer:
Influenced by the popes' initiatives, artists like Bernini integrated new grand urban spaces into their Baroque designs, exemplified by works such as St. Peter's Square, which played a significant role in the visual and emotional transformation of Rome.
Step-by-step explanation:
The urban visions of the popes during the Renaissance and Baroque periods led to transformative changes in the cityscape of Rome. Emphasizing the grandeur of Christianity, they funded and supported massive architectural projects that reshaped Rome's urban spaces. Pope Martin V's return to Rome in 1420 stimulated the construction of new grand avenues, monuments, and churches, aimed at not only enhancing the religious but also the visual experience of the city. The ambitious urban plans set forth by the popes led to the creation of iconic structures like the St. Peter's Basilica, a project that transformed a previously modest building into one of the world's grandest churches.
With the influx of pilgrims and the church's increasing economic power, Rome saw an emergence of new urban spaces that significantly influenced Baroque architects such as Gian Lorenzo Bernini, Carlo Fontana, Francesco Borromini, and others. Bernini's design of St. Peter's Square demonstrated the dynamic relationship between these new urban spaces and Baroque artistic approaches, integrating the surrounding cityscape with his architectural and artistic commissions. His work was emblematic of the Baroque emphasis on dramatic effects and the visual narrative that enveloped viewers into a religious and emotional experience in these newly defined urban settings.