It was built under the direction of the town council of Andernach in the period before 1440 and from 1448 to 1453 as a fortified watch tower within the town fortifications and known as the Rondentorne. It was probably erected on the site of the northwest corner tower of the Roman castellum or another, smaller, earlier structure. The builder in charge of the second phase of construction was municipal master builder, Philipp Preudemann. Whether he also acted as the architect is not known. Over the course of its history, the name of the tower varied from ronder thurn in the 17th century, Runder Thurmin the 18th/19th century and then Runder Turm thereafter. Master carpenter Johann was responsible for all the woodwork, including the installation and removal of the treadwheel operated cranes; Master Engel was the local smith. All the ropes and cables came from the workshop of Klaus von Mendig and Christian von Düsseldorf. Other masters named were Heinrich Schönbel, Arnold von Lieser and Johann Meyener. Even one name of the otherwise unnamed journeymen, workers, servants and assistants has been recorded: "In derselven wochen hait geoppert Peter Attenderngin 3 dage, y den dag 6 schillinge, macht 1 mark 6 schillinge." . The outside tower walls used to be plastered and coloured with a whitish to dark yellowish paint to underline the architectonic structure. Rests of the plaster and paint could be found until the mid-19th century.
Literature
Peter Adams: Kurzgefaßte Geschichte der Stadt Andernach. Andernach, 1955.
Werner Bornheim gen. Schilling: Stadt und Stadtmauer am Mittelrhein. In: Die kleine Stadt: Gestaltung der rheinischen Klein- und Mittelstädte. Rheinischer Verein für Denkmalpflege und Landschaftsschutz, Neuß, 1960
Paul Clemen : Die Kunstdenkmäler der Rheinprovinz - Kreis Mayen. 1. Halbband, Düsseldorf, 1941, 171 f.
Georg Dehio: Handbuch der Deutschen Kunstdenkmäler . Deutscher Kunstverlag, Munich, 1972
Franz-Josef Heyen : 2000 Jahre Andernach. Geschichte einer rheinischen Stadt. Stadtverwaltung Andernach, 1988, 1994
Victor Hugo: Le Rhin. Lettres à un ami. XIII. Paris, 1842
Manfred Huiskes: Andernach im Mittelalter: Von den Anfängen bis zum Ende des 14. Jahrhunderts. L. Rohrscheid, Bonn, 1980;
Hans Hunder: Andernach. Darstellungen zur Geschichte der Stadt. Stadtverwaltung Andernach, 1986
Hans-Jürgen Krüger: Inventar des Archivs der Stadt Andernach. Bd. 7 – Rechnungen, Koblenz, 1986, pp. 387–408
Barbara Lechler: Der Runde Turm. In: Tore und Türme. Stadtmuseum Andernach 1984, Heft 2, pp. 21–23
Klaus Schäfer : 550 Jahre Runder Turm. Begleitheft zur Sonderausstellung im Stadtmuseum Andernach vom 18. Mai bis 7. Dezember 2003, Andernach, 2003;