However the pope, apart from ad hoc aid and care for the needy as well as endeavors to provide the populace with grain, also found the time and means to enrich Rome with a new structure. It served the need of ever-growing pilgrimages to the tombs of holy martyrs, where the faithful searched for solace and support in difficult moments. One of such places was the tomb of St. Lawrence, located deep in a labyrinth of catacombs at via Tiburtina. The dark, narrow corridors, through which often ill and disabled pilgrims moved at a snail’s pace, required modernization and brand new logistics. A solution to this problem was the design of the Church of San Lorenzo fuori le mura (St. Lawrence Outside the Walls), which was situated directly above the tomb of the valued in Rome, saint deacon. The pope, ordered the erected building to be decorated and furnished not forgetting about himself either. In the triumphal arch of the church there is a beautiful mosaic with the enthroned Christ and saints, among whom is the figure of Pelagius holding a model of the funded church in his hand. The church patron himself – St. Lawrence - puts his arm around the pope in a protective gesture. At the initiative of the pope the presbytery of the Vatican Basilica (San Pietro in Vaticano) was also enlarged, while the altar was raised, in order for the tomb of St. Peter to be located directly above it.

The pope valued monks and willingly surrounded himself with them, entrusting them with functions in diplomatic missions, managing the city and granting them lands from which grain was brought in. He converted his house to a home for the elderly. He also suggested, which at that time had to be seen as revolutionary, introducing celibacy among priests and he even issued the appropriate regulations, however the idea met with such a strong resistance from the clergy, that it ultimately ended with a census of Church property in order to secure said property from the families of priests. On the other hand, the Council of Toledo in 589, where the leader of the Visigoths Reccared, moved away from Arianism, which meant a victory of the Roman orthodoxy (Roman Catholicism) in the Pyrenean Peninsula and strengthening the bonds between Spanish bishops and the pope, be can be counted among his successes.

Undoubtedly a significant achievement of Pelagius was supporting the diplomatic and spiritual career of his successor, the future  Gregory I, who was earmarked for this function even during the pontiff’s life.

Pope Pelagius died of the plague, while his body was laid to rest in the old Constantine Basilica of St. Peter. Since the reconstruction of this church his final resting place remains unknown.