After the completion of these doors, Ghiberti was widely recognized as a celebrity and the top artist in this field. He was given many commissions, including some from the pope. In 1425 he got a second commission for the Florence Baptistery, this time for the "east doors", on which he and his workshop (including Michelozzo and Benozzo Gozzoli) toiled for 27 years, excelling themselves. The subjects of the designs for the doors were chosen by Leonardo Bruni d'Arezzo, then chancellor of the Republic of Florence. They have ten panels depicting scenes from the Old Testament, and were in turn installed on the east side. The panels are large rectangles and were no longer embedded in the traditional Gothic quatrefoil, as in the previous doors. Ghiberti employed the recently discovered principles of perspective to give depth to his compositions. Each panel depicts more than one episode. "The Story of Joseph" portrays the narrative scheme of "Joseph Cast by His Brethren into the Well", "Joseph Sold to the Merchants", "The merchants delivering Joseph to the pharaoh", "Joseph Interpreting the Pharaoh's dream", "The Pharaoh Paying him Honour", "Jacob Sends His Sons to Egypt" and "Joseph Recognizes His Brothers and Returns Home". According to Vasari's "Lives", this panel was the most difficult and also the most beautiful. The figures are distributed in very low relief in a perspective space (a technique invented by Donatello and called "rilievo schiacciato", which literally means "flattened relief"). Ghiberti uses different sculptural techniques, from incised lines to almost free-standing figure sculpture within the panels, further accentuating the sense of space.