The key question for Francis is: Were deaconesses clergy in the way that they are today? Did ancient people mean the same thing by “deacon” that modern Catholics do? The strongest evidence for deaconesses comes from a late fourth-century Syrian document known as the Apostolic Constitutions. It contains instructions for the ordination of a deaconess by a bishop. The fact that they are ordained suggests that deaconesses are part of the clergy, but against this we have to put the statement made by a member of the Council of Nicaea in 325 c.e. that deaconesses “have no imposition of hands [that is to say they weren’t formally ordained by a bishop and thus they were] numbered only among the laity.”

The “historic openness” of the Church to female deacons is important because many Church teachings about the priesthood are based on the precedent set by Jesus. The reason why only men can serve as priests is not only because, as Francis said this week, the priest serves “in persona Christi” and as an “icon of the apostles” (for which gender is important), but also because Jesus only selected 12 men as apostles. If it turned out that Jesus selected women as apostles, let’s say Mary Magdalene, then that particular argument for the necessity of an all-male priesthood would be substantially eroded.