The name Byzantium refers to the ancient city on the Bosporus, now Istanbul, which Constantine renamed Constantinople in 330. It was not used thereafter, except in rare historical or poetic contexts, until it first took its new meaning in 1557 – when the German scholar Hieronymus Wolf published his "Corpus Historiæ Byzantinæ", a collection of historical sources about the Eastern Empire. Then from 1648 onwards, Philippe Labbe and fellow French Jesuits published the 24-volume "De Byzantinæ historiæ scriptoribus", and in 1680 Du Cange produced his own "Historia Byzantina". These endeavors further entrenched the use of the "Byzantine" label among French authors, including Montesquieu in the 18th century. Outside France in the Western world, it only came into general use around the mid-19th century, after Barthold Georg Niebuhr and his continuators published the 50-volume "Corpus Scriptorum Historiae Byzantinae".