We have seen Barnabas leaving Antioch in order to carry to the faithful at Jerusalem the contributions of their brethren in Syria, and arriving at Jerusalem in time to be present at several of the excitements occasioned there by the persecution of Herod Agrippa.[16.1] Let us now follow him again to Antioch, where, at this period, all the creative energy of the sect seems to have been concentrated. Barnabas took back a zealous assistant, his cousin John-Mark, the disciple of Peter,[16.2] and the son of that Mary at whose house the chief apostle loved to stay. Doubtless in calling this new co-worker to his aid, he had already in view the great enterprise in which they were to embark. Perhaps he foresaw the disputes it would occasion, and was well pleased to engage in it one who was understood to be the right hand of Peter, whose influence in general matters was predominant. The enterprise itself was no less than a series of great missions starting from Antioch and seeking the conversion of the world. Like all the great resolves of the early Church, this idea was ascribed to a direct inspiration of the Holy Ghost. A special call, a supernatural election, was believed to have been vouchsafed to the Church of Antioch while engaged in fasting and prayer. Perhaps one of the prophets of the Church, Menahem, or Lucius, uttered under the power of the gift of tongues the words intimating that Paul and Barnabas were predestined to this mission.[16.3] Paul was convinced that God had chosen him from his mother's womb for this task, to which thenceforth he exclusively devoted himself.[16.4] The two apostles took with them, as an assistant in the details of their enterprise, the John-Mark whom Barnabas had brought from Jerusalem.[16.5] When the preparations were completed, after fasting and prayer, and laying on of hands as a sign of the authority conferred by the Church itself on the apostles,[16.6] they were commended to the grace of God, and set out.[16.7] Whither they should journey, and what races they should evangelize, is what we are now to learn. The early missions were all directed westward, or in other words adopted the Roman empire for their scene of operations. Excepting some small provinces between the Tigris and the Euphrates under the rule of the Arsacides, the Parthian countries received no Christian missions during the first century.[16.8] Until the reigns of the Sassanides, Christianity did not pass eastward beyond the Tigris. This important fact was due to two causes, the Mediterranean sea, and the Roman empire.