As the clusters of New York theatres moved northward from Fourteenth Street in the 1880s, they reached Times Square in the mid-1890s just when the new electric street lighting began to be supplemented by electric signs. The Astor Hotel at 41st Street claimed to be the world's "most electrified hotel." Illuminated theatre marquees added to the nighttime illumination that around 1900 gave Broadway between 37th and 42nd Streets the epithet "Great White Way" or "the Rialto."
See also Electricity.
The Historical Dictionary of the American Theater. James Fisher.