A tale of Twin Cities

Most towns and cities have a single historic core or point of origin. Some towns and cities however are the result of the amalgamation of two -seldom more- (proto)urban settlements. There are several examples in continental Europe where there is also a specific name used for these types of towns and cities: for instance Doppelstadt in German and Dubbelstad in Dutch. The equivalent in English is: twin city, although the literal translation would be "double city", which is more apt and leaves no room for confusion with contemporary twinned cities.

There are several types of such Twin Cities. Some are fairly recent, where due to rapid expansion as a result of industrialisation or suburbanisation two hitherto separate settlements amalgamated. The way the City of London and the City of Westminster merged is a famous example of this process. However, no-one would typify   Westminster and London as a Twin City, but rather as part of London cum annexis. The older settlements have thus become part of an urban landscape. Another example of such an urban landscape is the Ruhr Area in the Rhineland.

The Twin Cities I'm speaking of here are pre-industrial settlements that stand out against their rural surroundings, either physically by a man-made border of some sort (paling, earth embankments, moat, walls) or legally (so-called freedoms and city rights bestowed on the settlement and its inhabitants). Such Twin Cities come in several types. The first type of Twin City is one where two nuclei are enveloped within a single urban designation; for instance a trade settlement and a clerical centre, or an administrative settlement and a civilian settlement. Examples of this type are Utrecht, Maastricht, Cologne, Lier and Leeuwarden (where three proto-urban Oldehove, Nijehove and Hoek settlements merged into a single city).

The second type involves the designation of a new trade or government centre opposite or next to a pre-existing settlement. This was often a way of re-establishing the power of the Overlord over a local Nobleman. This type of settlement is widespread in the Low Countries; examples include Oisterwijk, Vught, Eindhoven and Geel. Most of the Twin Cities of this type developed into towns or even market villages if not well positioned rather than cities.

A third type of Twin City involves cities that were born out of a union of two separate dominions. Most often these separate dominions are ecclesial in nature with two nearby settlements -more often than not separated by water as a borderline- and a church and market square each. The most famous example of this type is Nuremberg.  

A fourth type involves the conscious duplication by building a new city next to a pre-existing one, often across a borderline in the shape of  a river or brook. This type is rare and the best known example is Brandenburg on the Havel.

The four types of Twin Cities: (1) Multiple Nuclei, (2) Adjoining Nucleus, (3) United Nuclei and (4) Duplication of Nuclei.