Bits & Bobs : Finds from a research excavation of Birka’s rampart: A study with focus on material distribution and metal conservation

Abstract: In the spring of 2018, a prospection and subsequent research excavation of a previously unstudied area related to the rampart of the Viking age town of Birka, Sweden, was undertaken by students and professors from the archaeological science department affiliated with Stockholm University.The purpose of this paper is to examine and categorise the various excavated finds, the ensuing conservation and preservation of the metal objects as well as to investigate the context and possible function of the site regarding the spatial distribution of said finds.The main method used is that of metal conservation with the wet-chemical technique EDTA; a method that was deemed adequate for the treatment of the dry metal finds from the rampart excavation.The conservation and categorisation suggest that the metal posts consist of assorted metal objects, predominately rivets and nails as well as unidentified fragmented objects; the occasional slag fragment was evident. The material category of clay and ceramics contains assorted burnt clay and ceramic sherd fragments, some with decoration. Whetstone (or hone stone) and flint fragments make up most of the stone finds while the category of glass consists of a few bead fragments. The bulk of the osteological material consists of burnt and unburnt animal bones, some with slaughter marks in the form of cuts and hacks. Two human bone fragments were found; a humerus- and cranial fragment.Post holes and charcoal in the context of the rampart suggests the possibility of wooden supports and/or a superimposed wooden structure on the rampart itself that likely burnt at some point in time. The interpretation of the excavated area, based on the distribution of the finds and material categories, is that of a dumping site for discarded town refuse, most likely set against or near a walled construction; the rampart. The dating of the site is based on object similarities as well as stratigraphy and set to; Early to Late Viking Period, c. A.D. 820-1000(1150).The analyses, materials and the stratigraphy of the site together with a contextual analysis of the objects in question furthers the knowledge of Birka’s rampart and will enable future scientific inquiries into this specific rampart as well as similar fortification structures.