The individual pictures are like the frames in a movie film or pages in a book. Perhaps the most elaborate frames of all were the Medieval and Renaissance altarpieces, with their mountain ranges of pointed peaks. They look pretty old to us now, but Jacob Burckhardt writes that the great tradition of modern European easel painting started with the Italian Renaissance altarpiece. The altarpiece was on the cutting edge of Italian painting, using the most advanced methods and materials. There were no rules for the design of an altarpiece, so it was a place where artists could experiment with new methods and materials.
Altarpieces show continual change over the years, both in shape and subject matter.
They were regularly replaced by the latest model, the old altarpiece often cut up and pieces scattered in various galleries. Duccio's super-altarpiece, the Maesta was a big deal in 1311. According to Hartt, it was carried from his studio to the cathedral in a triumphal procession, the people carrying lighted candles and torches, to the sound of all the bells of the city, and the music of trumpets and bagpipes. But Vasari writing in 1550 says he could not even locate the old altarpiece. But we can see most of it today in the Cathedral Gallery in Siena a few years ago.