Catholics believe that priests should wear special robes to express their importance. This was shown by priests being called divine beings, this was presented by priests wearing rich, elaborate clothing. In the catholic church priests had more power than the protestant priests ever had, because they have to wear plain clothes and were not considered very much as divine beings.
The only priests who are known to wear sandals, and have to, are Discalced Carmelites. The "Discalced" means that they do not wear shoes, it is not the most important thing about that particular reform of the Order, but it is noticeable, and the name has certainly stuck. Other Order priests wear sandals, but none of the others have sandals as a prescribed part of their habit.
Medieval scribes were clerics, a word that came to be changed to clerks. They wore clothing similar to those of teachers, monks, or priests. That is to say the clothing was simple, somber, and neat. The cut would have been very conservative for the time and place, but that varied with time and place.
Answer from a Catholic Okay, I wasn't around back then, and I don't know anybody that was. But, I assume that since all clothes were handmade back then, that most people didn't have a lot of clothes. I'm pretty sure that priests just wore their habit if they were religious and, if they weren't, then they wore their cassock (soutaine).