There is a place in Jerusalem today called The Cenacle or “dining room.” It comes from the Latin cenare, meaning to dine, and it is traditionally believed to be the very site where Jesus and his disciples shared their last meal, before he was crucified. Both Mark and Luke use the Greek anogeon (G508 – Mark 14:15; Luke 22:12), but Luke uses a different Greek word, huperoon (G5253) in Acts, where the 120 met together (Acts 1:13), and where Dorcas, whom Peter raised from the dead, was laid out (Acts 9:37, 39) and where Paul met with the brethren from Asia (Acts 20:8). Yet, the word probably indicates the same type of room where the Last Supper was held.
In each of the accounts of the Apostles being together after Jesus’ death, they were probably meeting in the Upper Room (cf. Luke 22:12; Acts 1:13), the same room in which Jesus shared his final meal with them. This room was probably part of Mary’s home (cf. Acts 12:12), which also may have been a synagogue and later a meeting place for the nascent Church at Jerusalem. In the first century synagogues doubled as inns, where pilgrims stayed, while visiting Jerusalem.
When Jesus told his disciples where he planned to eat the meal for the Passover, he sent them to inquire of the goodman of the house, what guest-chamber he had set aside for Jesus’ meal with his disciples (Luke 22:9-11). The Greek word for guest-chamber (G2646) in Luke 22:11 (see also Mark 14:14) is the same word translated inn where there was no room for Jesus when he was born (cf. Luke 2:7)
In places such as this we would find large furnished rooms that could be used for banquets or for lodging. They were public places as we see in Luke 22:10, because Jesus told the disciples to follow the male servant and continue to the house (G3614). They were to speak with the good-man of the house, (G3614) or the lord or master of the house (G3617 – Mark 14:14). This title answers to the ruler of the synagogue. There were hundreds of synagogues in Jerusalem, accommodating many Hellenistic Jews from around the Empire. They couldn’t possibly support themselves, unless they doubled as inns for pilgrims coming to the annual festivals.
There is an ancient inscription on a stone found in Jerusalem called the Theodotus Inscription, it dates to the first century AD. It was uncovered in 1913 near David’s City (Mount Ophel) in Jerusalem. The inscription is in Greek and comes to us inscribed in limestone. It is on display today in the Rockefeller Museum in Jerusalem. The English translation is:
“Theodotus, son of Vettanos, a priest and an archisynagogos, son of an archisynagogos grandson of an archisynagogos, built the synagogue for the reading of Torah and for teaching the commandments; furthermore, the hostel, and the rooms, and the water installation for lodging needy strangers. Its foundation stone was laid by his ancestors, the elders, and Simonides.”
Luke seems to suggest in Acts 1:13 that the Apostles stayed in this Upper Room when they were in Jerusalem, that is, as their residence. This would be in perfect harmony with the Theodotus Inscription mentioned above. Synagogues were used for many purposes, including meeting on the Sabbath, schools, banquets, temporary meeting places, lodging and even to lay out a body before burial. Moreover, Luke seems to show that it was the place where the 120 were gathered together when the Holy Spirit fell upon them on Pentecost Sunday.
Thus, if all of the above is logically so, Mary’s home (Acts 12:12) was probably a synagogue, and had served as the place for Jesus’ final meal with his disciples before he died. This same place seems to have become a meeting place for the first believers in Jesus.
 That is “ruler of the synagogue”. The Greek word is G572 and is the same word found and so translated in Matthew 5:35, 36 and 38.