In the four spaces besides the two doors, the "Sacred factories", which are the most significant buildings in Israel's history, are represented.These latter were a major subject to study and search for the monks, namely because of their symbolic and historical relevance. The representation of Israel's High Priest is based on chapter 28 of the Exodus in Montano's Bible, which was a very up-to-date source for the frescoes' themes (the frescoes were painted no later than two years after the publication of Montano's Bible), and its pictures, reproduced in the Library, aimed at joining the didactic aspect (the visual representation helped the monks studying the Scriptures to better understand some very complex and obscure biblical texts) and the symbolic aspect (the presence in the Library's privileged space of those basical expressions of God's wisdom, which are revealed to men through their holy structures). The fresco is on the left of the northern door and it represents Israel's High Priest Aaron witth all his sacred vestment and instruments of ritual sacrifice.