Historically, the use of the medium of stained glass in the Eastern Orthodox Church has been very little explored. One likely reason is the late discovery of stained glass and its flowering in the context of the church architecture of the Roman Catholic Church from the twelfth century in northern Europe, postdating the Great Schism of 1054. The Wissembourg Head (1060) is the earliest surviving painted head of Christ on glass, and marks the beginning of the architectural revolution in France, to which the development of stained glass was inextricably linked.