Peter and Paul founded the church of Rome -- an inscription was found in the necropolis in proximity to a bone box during the excavations in Saint Peter's in 1950 as I recall -- "Peter is here".

It was always a point made from very early times that Rome was the church of Peter. As opposed to places like Alexandria for example whose status came from it being the see of a disciple of Peter.

Something else I seem to recall is that one of the leg bones was different -- what would be expected from a Galilean fisherman always putting one leg on the side of a boat to haul in a fishing net.

The final resting place of a number of Apostles is more or less known -- Ss Simon and Jude are in Saint Peter's, Saint Paul is buried in Saint Paul Outside the Walls in Rome, Saint James the Greater is at Compostella in Spain, Saint Bartholomew is in a church on an island in the Tiber in Rome, Saints Philip and James the Lesser have their own church in Rome I think.

Catholic tradition has always held that Peter moved to Rome, taught there as a teacher, and then died there.

Other Christian circles, and a large swathe of historians, disagree on this front. However, it is one of the founding points of the Petrine Primacy, or the reason that Saint Peter is seen as the First Pope of the Catholic Church.