Theodor Mommsen's monumental work, 'Römische Geschichte,' consisting of all six volumes, is a hallmark in the study of Roman history. Mommsen's meticulous research and detailed narrative provide a comprehensive and authoritative account of ancient Rome, covering political, social, and cultural aspects of the Roman civilization. His writing style is engaging and accessible, making this scholarly work suitable for both academics and general readers. 'Römische Geschichte' is considered a classic in the field of Roman history, setting the standard for historical scholarship in the 19th century and beyond.