Santa Maria del Popolo
Soon after its transfer to the prestigious Lombard Congregation Santa Maria del Popolo was reconstructed between 1472 and 1477 on the orders of Pope Sixtus IV. This was part of the ambitious urban renovation program of the pope who presented himself as "Urbis Restaurator" of Rome. The medieval church was entirely demolished and a new three-aisled, Latin cross shaped basilica was built with four identical chapels on both sides, an octagonal dome above the crossing and a tall Lombard style bell-tower at the end of the right transept. The result of this reconstruction was an early and excellent example of Italian Renaissance architecture in Rome. In spite of the many later changes the basilica essentially kept its Sistine form until today.
Old St. Peter's Basilica
By the 15th century the church was falling into ruin. Discussions on repairing parts of the structure commenced upon the pope's return from Avignon. Two people involved in this reconstruction were Leon Battista Alberti and Bernardo Rossellino, who improved the apse and partially added a multi-story benediction loggia to the atrium facade, on which construction continued intermittently until the new basilica was begun. Alberti pronounced the basilica a structural abomination: