How did Andrea Mantegna change the design of sacra conversazione altarpieces?

Andrea Mantegna revolutionized the design of sacra conversazione altarpieces—paintings depicting the Madonna and Child with saints—by introducing advanced principles of illusionism.1

In his San Zeno altarpiece (1459), Mantegna achieved this by placing the figures within a unified space that appears continuous with the physical frame of the artwork. He accomplished this by aligning the carved half-columns of the altarpiece's frame with the painted piers depicted on the front plane of the picture space. This technique effectively transformed the frame into the exterior of the temple-pavilion architecture shown in the painting, successfully conjoining the idealized, sacred sphere inhabited by the Virgin Mary with the actual space occupied by the beholder.12

By utilizing these physical and optical devices, Mantegna moved beyond traditional compositions, creating a more immersive and realistic experience for the viewer.12