In former times there were “schools of art.” In Italian art, we speak, for example, of the Florentine School, the Venetian School, the Roman School; or we speak of the Flemish School, and Dutch Schools and so on. In each case the artists, living in a certain city or country, had sufficient resemblance among themselves in their motives and methods of painting to produce a certain separate style. So, to-day, if an expert sees an old picture, he is able to say at once and, more often than not correctly, that it belongs to such and such a school.