Complex sentence: At one time it was the Hampshire part of the cross-county parish of Stratfield Mortimer (mostly in Berkshire), it became an ecclesiastical parish in 1870 (the church, St Saviour, having been built in 1854) and a civil parish in 1894.
Split into simpler sentences: At one time it was the Hampshire part of the cross-county parish of Stratfield Mortimer (mostly in Berkshire). It became an independent ecclesiastical parish in 1870-the church of St Saviour having been built in 1854-and a civil parish in 1894.