Saint Wilfrid is believed to have arrived in present-day Hampshire in 648 AD and introduced Christianity to the area around the River Meon. St Peter's Church at Titchfield was one of several churches founded in the period between this and the Norman conquest of England; like the county's other early churches its parish served villages across a wide area. Stonework in the lowest stage of the tower, originally a porch, survives from the Anglo-Saxon era, probably from around 700 AD. Also of ancient origin is St Mary's Church at Portchester, dated definitively to the mid-1130s and "a first-class Norman monument" retaining its original cruciform plan. By the end of the Middle Ages only one other church in the area covered by the present borough: Fareham town's parish church, St Peter and St Paul, originally a small chapel but now greatly extended. Its appearance was transformed in the 18th and 19th centuries, but the medieval chancel is now a side chapel.