Q. How many persons were in the Upper Room for Pentecost?
A. Here’s a reply from Father Reginald Martin:
The Acts of the Apostles relates that after Jesus’ ascension the eleven apostles “went up to the upper room where they were staying” (Acts 1:13). The text goes on to say that they were accompanied by “some women, and Mary the mother of Jesus, and his brothers” (v. 14).
Mary brings the number to twelve, but who are the other women? And how many were they? The editors of the Sacra Pagina New Testament Commentary Series (Liturgical Press) identify the women as those who, Luke writes, witnessed Jesus’ death and burial (see Lk 23:49,55). Their reward is to receive the outpouring of the Spirit. Luke does not give a number, but he names Mary Magdalene, Joanna and “Mary the mother of James” among the women who share the news of the Resurrection with the apostles (Lk 24:10).
In Matthew’s Gospel account the crowd names four men — James, Joseph, Simon and Judas — as “brothers” of Jesus (see 13:55). If we assume all these individuals who are named in the Scripture were gathered in the Upper Room, we have a group numbering 19. The spot that archaeologists and scholars have identified as the Upper Room is not immense, but it could easily accommodate this number of individuals.