Although I have heard of a bride and groom walking down the aisle together, I haven’t heard of it being a “Catholic tradition” that predates the tradition of a father escorting his daughter (or that the father escorting his daughter was a “Protestant tradition”). The ancient Catholic tradition of which I *had *heard is that during the Middle Ages the bride and groom would be married at the door of the church and then the whole wedding party would process inside for the Mass.
In any case, whatever their origins, the Church doesn’t proscribe either of the customs that you described (although the medieval tradition I mentioned is no longer done). For the most part, the line-up of the liturgical procession at a Catholic wedding can be drawn up in a number of different ways, depending on the preference of the bride and groom and upon the agreement of the nuptial presider. If a bride and groom want to enter the church and process down the aisle together, they may. If they want to have the father escort the bride, they may.
As a side note, it *is *a non-Catholic tradition for the father to “give away” the bride. “Giving away” the bride is when the presider asks “Who gives this woman in holy matrimony?” and the father responds “I do” (or, in a modern updating, “Her mother and I do”). It is not part of Catholic wedding ceremonies because Catholic marital theology insists that the bride and groom must willingly give themselves to each other for the sacrament to be valid. This non-Catholic custom should not be confused with the father escorting the bride down the aisle, which is an entirely separate issue.
