http://www.cwu.edu/~robinsos/ppages/resources/Theatre_History/Theahis_15.html
This website overviews how modern theatre was developed by the works of theatre innovators and directors such as Richard Wagner, Germany's Georg II, and Belasco. The website goes into great detail about these individuals, but says very little about other factors that helped create what we today consider modern theatre. The website also covers a short time span, from 1875 to only 1915. This leaves out almost one hundred years of modern theatre. This website would be very useful for someone studying the early ages of modern theatre and individuals who helped to shape it.