This left-sided detail, from an oil-on-oak panel by Hans Memling, shows Jesus (with his disciples) celebrating Passover dinner on Thursday evening (referred to as "Maundy Thusday"), a few hours before Judas betrayed him. Look to the left, in this view of Jerusalem.
Memling painted this work - Scenes from the Passion of Christ - between 1470-71. It is now at the Galleria Sabauda in Turin, Italy.
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Image online, courtesy Web Gallery of Art.