Age, dimensions and classification - a multi-causal absence of three-aisled longhouses from aerial photographs of western Jutland, Denmark

摘要

This article focuses on a significant parameter associated with the interpretation of cropmarks of three-aisled longhouses on aerial photographs of western Jutland, Denmark. Between 2008 and 2013, during the first part of the project 'An aerial view of the past - aerial archaeology in Denmark', 672 three-aisled longhouses were discovered. These longhouses have been dated typologically, identifying only four houses from the Early Bronze Age (ca 1700-1100 bc) and showing no recorded examples from the Late Bronze Age (1100-500 bc). The remaining longhouses fall primarily within the period from the Early Iron Age to the Viking Age (ca 500 bc-ad 1050). The absence of longhouses from the Bronze Age is presently explained as a consequence of age and dimensions. Two factors that revolve around the possibilities of cropmark occurrence. In this article, it is suggested that the method of classification used to interpret longhouses on aerial photographs is of crucial significance with respect to the virtual absence of Bronze Age examples. The typological problems associated with visual classification are outlined, after which the possible latent presence of Bronze Age longhouses in the aerial photograph database is investigated. The problems are addressed via a series of principal component analyses (PCAs), employed as a classification tool. The PCA classification of the longhouses is based exclusively on the arrangement of the internal roof-bearing posts. The analysis uses data from 203 excavated longhouses, which are compared with 120 longhouses recorded on aerial photographs. The analysis identified 14 longhouses that could potentially be from the Late Bronze Age, both with respect to internal roof-bearing construction and visual appearance on aerial photographs. This leads on to a discussion of the typological problems associated with identifying longhouses from the Late Bronze Age and Early Pre-Roman Iron Age, together with a weighting of the factors: age, dimensions and classification.