More of St Alban's

While visiting St Albans in May I also managed to snap some of the remains of the medieval paintings on the piers of the nave. Since the Crucifixion features prominently on each of these west facing sides it seems not unlikely that  there were altars below them originally. Before Vatican 2 concelebration was extremely rare and a multiplicity of altars enabled several priests to celebrate mass more or less simultaneously- an important consideration in a monastery where many of the monks would be priests.
On the subject of concelebration: I'm not against it as such- it just seems a waste of priests when by each celebrating individually the numbers of masses could be increased and the opportunities for us laity to attend mass similarly multiplied.