I will only talk here about the sublime "Last Supper" by Andrea del Castagno (1447), which I was able to enjoy through an in-depth guided tour.
The iconographic theme of the Last Supper is far from new in Florence, but here it shows great originality. The dinner takes place in a quadrangular room, which the spectator can see because one of the four walls has been eliminated. The room is designed according to rigorous perspective criteria, the strength of which is accentuated by the four large marble quadrangles of the back wall. The fact that you can see the roof of the room (which according to the criteria of perspective should be out of sight) is an understandable license that the artist has taken.
The visual rendering of the white cloth spread on the table is astonishing: the cloth seems to be made of a stucco bas-relief rather than a painted one.
The human figures are defined with clear outlines, almost sculpted, and their faces are rendered through a characterization of their respective physiognomies, very different from each other, and which aim to make the characters of each one shine through their faces:: observe for example the faces of the apostles Thomas and Matthew, then of Judas, the only one sitting on this side of the table for those watching.
In my opinion, it's an absolute masterpiece, among the greatest of the Renaissance, albeit by a painter defined (unjustly?) as minor.