This study presents a framework for assessing the cultural asset values of historic sites around mosques. Case studies are selected from provinces of Manisa, Turkey, namely, Çarşı in Salihli with its new urban development and Pazaryeri in Gördes that is abandoned and currently considered as an archaeological site. Literature review, archive research, historical research, comparative study, and site survey are carried out to evaluate the urban development of site neighborhoods with a retrospective perspective. An approach presenting the effects of urban transformations on the cultural asset values of the historic neighborhood centers is proposed. The cases reveal that the urban aesthetic is nearly all lost today, but the holiness of each site preserves its authenticity while the historic land use is sustained. Their preservation problems are lack of maintenance and abandonment due to disasters, illegal interventions, inappropriate development plans, and unsuitable restoration approaches. The principles proposed for managing these historic environments consider their cultural asset values in relation to urban history, development of coherent strategies for their presentation, and participation of all actors to their preservation and development.