This work presents the formulation of a conceptual model for architectural heritage, a meta-model, which attempts to encompass the common aspects of diachronic architectural theories for architecture composition. The model incorporates definitions of some of the essential theories that represent the underlying conceptualization of the information contained in an architectural work and its aim is to create a particular understanding that can be used to design and build monument inventories. A practical application of the above model is the derivation of ARMOS (Architecture Metadata Object Schema), a metadata schema underlying this model, consistent with the recording principles of ICOMOS for monuments, aiming at reducing semantic heterogeneity in the description of architectural works, especially historic buildings.