During the reign of Grand Prince Ivan III (1462-1505), many Italian and other Western European craftsmen, architects and engineers were brought into Russia to work on various projects. The Italians (and by extension other non-Russian speakers from Western Europe), were known in Russia as Friazi, a word that developed from the Greek term φραγκος/frangkos — франк/frank — meaning a “Frank.” That is the term by which the Western European Crusaders were known to the Byzantines.
That word for Western Europeans accounts for why, in literature on icons, we sometimes find the term фрязь/fryaz applied to the later style of icon painting favored by the State Orthodox Church. It is often simply called the “Western” or “Italianate” style. It signifies the more realistic, heavily European-influenced manner of painting that began in Russian iconography in the latter half of the 17th century and gradually replaced the old strongly stylized manner that continued to be used by the Old Believers right into modern times. So this more “Italian” or Western European way of painting icons came to be known as fryaz or the Фряжское письмо/fryazhskoe pis’mo (Frankish painting) or the фряжская/fryazhskaya manera (“Frankish manner) or style.
We can easily see the difference between the traditional stylized painting continued by the Old Believers —
And the “Western” manner found in State Church Icons —