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Hermann Detering on the Clementines

Many scholars concur that "Simon Magus" in the Ebionite influenced works such as the Clementine Homilies (sometimes misleadingly referred to as the Pseudo-Clementine Homolies) represents a name-replacement for Paul. The purpose was to protect Paul from embarrassment of what the Clementines in the early church recorded as part of the history of Paul.

The Berlin Pastor, Hermann Detering (born 1953), believes these works are actually historical accounts of the life of Paul. And thus, it demonstrates Peter went to Rome not to work with Paul so much as to confront him. As the Wikipedia article on "Hermann Detering" explains: 

Many scholars, since Ferdinand Christian Baur in the 19th Century, have concluded that the attacks on "Simon Magus" in the 4th Century Pseudo-Clementines may be attacks on Paul. Detering takes the attacks of the Pseudo-Clementines as literal and historical, and suggests that the attacks of the Pseudo-Clementines are correct in making "Simon Magus" a proxy for Paul of Tarsus,^[3] with Paul originally having been detested by the church, and the name changed when Paul was rehabilitated by virtue of forged Epistles correcting the genuine ones.^[4]

Detering's argument expands beyound the Clementines to include other apocrypha, arguing that Simon Magus is sometimes described in apocryphal legends in terms that would fit Paul, though most significantly does so in the Clementine Recognitions and Homilies.

Detering contends that the common source of these documents may be as early as the 1st century, and must have consisted in a polemic against Paul, emanating from the Jewish side of Christianity. Paul being thus identified with Simon, Detering argues that Simon's visit to Rome (in the Clementines) had no other basis than Paul's presence there, and, further, that the tradition of Peter's residence in Rome rests on the assumed necessity of his resisting the arch-enemy of Judaism there as elsewhere. Thus, according to Detering, the idea of Peter at Rome really originated with the Ebionites, but it was afterwards taken up by the Catholic Church, and then Paul was associated with Peter in opposition to Simon, who had originally been Paul himself.  Rufinis created a revised Clementine to allow for such myth and hero worship to turn toward Paul.

Hence, Peter and Paul were not allies at Rome because the Clementines depict a confrontation between Simon Magus (Rufunis' cipher for Paul) and Peter. And Detering defends that the Clementines are historical and not fictional accounts. He means when Paul was rehabilitated later -- in Constantine's era, the Clementines were edited to change "Paul" to "Simon Magus." This makes sense once you read the Clementines and recognize the individual "Simon Magus" can be no other than Paul in various discreet places.