During the work of the Augsburg-team on the Forum of Pompeii, we started an related but indipentenly financed project with Klaus Müller as architectural historian. Its aim is to study for the very first time the architecture of the honorific arches (4 on the Forum, one in Via di Mercurio) on the Forum and its neibourghood, to reconstruct their form and marble facing and to fix their dating. In 2006, a team under the direction of Prof. Ringle from Karlsruhe executed a photogrammetric documentation of all preserved arches. From February 2007 onwards, the architectural historian Klaus Müller secured a grant from the Fritz Thyssen Foundation that enabled him to evaluate, verify and extend the data from these studies. The precise mapping of fixing holes that originally held marble facings, for example, facilitates the first accurate reconstruction of the original appearance of these arches. The data gathered from the arches situated to the East of the Capitol is of particular interest in this respect, as its asymmetrical plan results from its position on top of the foundations of the wall that originally surrounded the forum. The evaluation of data shows not only that this arch must have been constructed after the AD 62 earthquake, but also that it subsequently underwent one or several changes to its design. This revises the current understanding of both the date and identification of the arch entirely. Müller\'s research was completed during the Spring campaign 2009.