The opening verse identifies the apostle Peter as the sender of the letter, and the concluding greetings reveal that Silvanus did the actual writing. Peter would have dictated what he wanted the letter to contain, and Silvanus appears to have had the liberty to word the thoughts the apostle expressed, doing so in correct literary style. (1 Peter 1:1; 5:12)
 
At the time, Peter was in Babylon, which many consider to be a cryptic or code name for Rome. No specifics about any individuals in the letter would have required using a cryptic name in an effort to protect them from possible persecution. Nothing in the context itself explains why Peter, unlike Paul, would have chosen to use the designation Babylon instead of Rome. Moreover, the order in which the regions where the intended recipients of the letter lived reflect what one would expect for an individual who would be located in an eastern region, not a western city. The westernmost Roman provinces (Asia and Bithynia) are referred to last in 1 Peter 1:1.

Many Jews lived in Mesopotamia under Parthian rule. According to Josephus (Antiquities, XV, ii, 1, 2), the high priest Hyrcanus II, whom the Parthians had taken captive, was set free by the Parthian king and given “a habitation at Babylon, where there were Jews in great numbers.” This was about a century before 1 Peter was written. The presence of Jews from Mesopotamia and Parthia for the festival of Pentecost about seven decades after the time Hyrcanus II lived in Babylon suggests that Jews still resided there even though the city itself was in a state of decline. (Acts 2:9) Peter, along with James and the apostle John, had agreed with Paul and Barnabas that he would minister to the Jews. (Galatians 2:7-9) His spending time in Babylon among fellow Jews would have been in line with this decision, and so one could conclude that Peter sent his letter from Babylon in Mesopotamia.

Very ancient tradition, however, does not support this conclusion. Eusebius, in his Ecclesiastical History (II, xv, 2), wrote, “Peter makes mention of Mark in his first epistle which they say that he wrote in Rome itself, as is indicated by him, when he calls the city, by a figure, Babylon, as he does in the following words,” which are then quoted from 1 Peter 5:13.

Many are inclined to accept the ancient tradition that equates Babylon with Rome, especially in view of what various early writers have said about Babylon in Mesopotamia. According to Pliny the Elder (Natural History, VI, 30), Babylon had “been drained of its population in consequence of its vicinity to Seleucia, founded for that purpose by Nicator.” In his Geography (XVI, i, 5), which he completed early in the first century CE, Strabo wrote that Seleucia “at the present time has become larger than Babylon, whereas the greater part of Babylon is so deserted that one would not hesitate” to apply to it the expression of one of the comic poets, “The great city is a great desert.” These comments about the state of Babylon would seem to suggest that the city could hardly have been a place where Peter would have gone.

If Babylon actually means Rome, the way the regions are listed in 1 Peter 1:1 might be explained as suggesting that a messenger with the letter would have gone to Pontus first, the most distant region, and then traveled through Asia Minor, returning to Rome from Bithynia. Nevertheless, it does seem puzzling that Peter would say “Babylon” instead of “Rome,” as did Paul. Traditional accounts speak of Peter’s martyrdom in Rome but do not make it possible to draw any definitive conclusions about just when he might have arrived. The Scriptural record is completely silent about any activity of Peter in Rome, and he is not mentioned in Paul’s letter to the Romans.

While ancient accounts indicate that Babylon in Mesopotamia had sunk into obscurity, one cannot be absolutely sure about what the situation may have been about the size of the Jewish population there in every decade before Peter’s death. There are historical indications that part of Babylon was inhabited before and after his time.

According to the Epitome of Dio Cassius (Book LXVIII, 30), Trajan went to Babylon because of the city’s fame and on account of Alexander the Great’s having been there, but he only found “mounds and stones and ruins.” Trajan reportedly offered a sacrifice to the “spirit” of Alexander “in the room where he had died.” This indicates that not all of Babylon lay in ruins and suggests that there were inhabitants who knew about the location of this room.

Josephus relates that Jews living in Mesopotamia, especially those residing in Babylonia, came under intense persecution. This occurred about the middle of the first century CE, and Jews living in the city of Babylon were affected. Although many then fled to Seleucia, others remained. Josephus reports that five years after the major Jewish flight from Babylon, those who stayed in the city experienced a pestilence, prompting more of them to depart. It is not possible, however, to assign specific dates to these developments. (Antiquities, XVIII, ix, 1, 8, 9)

 
Definitive conclusions about how the designation Babylon is to be understood are not possible, especially since traditional accounts are not always reliable. The important aspect is the message contained in Peter’s letter, and so the place from which the letter may have been sent is really immaterial.