Ya know I got into a self made study of others who Painted the Last supper.
What I was interested in I think part of a mosaic was found is that the theory of in the Roman/Greek time folks did not sit around the table as in DaVincis painting.
It would have been more like lounging around the table and when Jesus feet were washed with the expensive oil he would have been reclined at the table arangement of three rather than one long so his feet would have been easily accessible not the gal going under the table to wash them...
None of it matters it was just something to amused myself with at the time.
The Renaissaince and earlier artists painted biblical cenes in clothing and with furnishings and customs more appropriate to the time of the artist.
Peter turning about, saw that disciple whom Jesus loved following, who also leaned on his breast at supper, and said: Lord, who is he that shall betray thee?
It's easy to imagine all of the apostles leaning on their left elbows and a young St John, seated to Jesus' right, leaning back against Jesus' chest so that he can see Christ's face as he speaks.