Christian churches have existed in Derbyshire since the Anglo-Saxon era, and some of the Grade I listed churches have retained Saxon features. St. Wystan's Church, Repton, has a complete Anglo-Saxon crypt, and some churches have fragments of Anglo-Saxon stones incorporated in their structure, including All Saints' Church, Aston-upon-Trent, and All Saints, Bakewell. More churches contain elements of Norman architecture. The architectural historian Nikolaus Pevsner identified the two most important Norman churches as St Michael with St Mary's Church, Melbourne, and All Saints' Church, Steetley, the latter being little more than a chapel. Most of the churches in the list date from the 15th century or before, and the predominant architectural style in the list is Gothic. Only three churches in the list originate after 1600, namely St Saviour's Church, Foremark, built in 1662, St Mary's Church, Cromford, the building of which started in 1792, and Church of All Saints, Hassop, built in 1816–17, and the only Neoclassical church in the list.