In the 11th century the Normans were among Europe's leading exponents of Romanesque architecture, a style which had begun to influence English church building before 1066, but became the predominant mode in England with the huge wave of construction that followed the Norman Conquest. The Normans destroyed a large proportion of England's churches and built Romanesque replacements, a process which encompassed all of England's cathedrals. Most of the latter were later partially or wholly rebuilt in Gothic style, and although many still preserve substantial Romanesque portions, only Durham Cathedral remains a predominantly Romanesque structure (along with St Alban's and Southwell, abbey churches in the medieval period). Even Durham displays significant transitional features leading towards the emergence of Gothic. Romanesque churches are characterised by rounded arches, arcades supported by massive cylindrical piers, groin vaults and low-relief sculptural decoration. Distinctively Norman features include decorative chevron patterns.