Viking ring fortress
From Wikipedia, the free encyclopedia
Trelleborg is a collective name for six Viking Age circular forts, located in Denmark and the southern part of modern Sweden. Five of them have been dated to the reign of the Harold Bluetooth of Denmark (d. 986). The fort in Borgeby has been dated to the vicinity of 1000 AD, so it is possible that it too, was built by the same king.
This type of fortrification is also named after the first discovered example; Trelleborg near Slagelse, excavated 1936-1941). All trelleborge have a strictly circular shape. This structure may also be (partially) encircled by an advanced rampart but this part of the structure is not necessarily circular.
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[edit] List of trelleborge
- Aggersborg near Limfjorden, Denmark.
- Borgeby north of Lund at Lödde Å in Skåne, modern Sweden.
- Fyrkat near Hobro, Denmark.
- Nonnebakken in Odense, Denmark.
- Trelleborg near Slagelse, Denmark.
- Trelleborg in Trelleborg, Skåne, modern Sweden.
Traditionally, the name Trelleborg has been explained as a fort built by slaves (the Danish word for slave being træl), but the word trel (pl trelle) in a more plausible explanation. This relates to the wooden staves covering both sides of the protective circular walls.
[edit] Comparison of the six fortifications
| Name | Inner diameter | Rampart width | Number of houses | Length of houses |
|---|---|---|---|---|
| Aggersborg | 240 m | 11 m | 48 | 32.0 m |
| Borgeby | 150 m | 15 m | ||
| Fyrkat | 120 m | 13 m | 16 | 28.5 m |
| Nonnebakken in Odense | 120 m | |||
| Trelleborg near Slagelse | 136 m | 19 m | 16 | 29.4 m |
| Trelleborg in Trelleborg | 125 m |
The ring castles and the contemporary bridge over Ravning Enge/Vejle Å (Vejle river) — together with minor bridges erected on Zealand (Bakkendrop bridge between Gørlev Tissø and Risby bridge by Præstø) and Lolland (over Flintinge river) — differ clearly from others from the Viking Age. Unlike other ring castles from the period the ring castles which follow the Trelleborg model are constructed after a strictly geometrical plan and measured with the Roman foot. The pointed bottoms of the moats is another element borrowed from the Ancient Romans.
In spite of searches no real parallels have been found in the rest of Europe. On the coasts of the Netherlands and Belgium there are ring castles with certain points of resemblance and on the island Walcheren there are the remnants of a castle with gateways in the four points of the compass, combined with streets. Trelleborg (near Slagelse) and Fyrkat have been dendrochronologically dated to 980. The four others have been dated to roughly the time. Around 974 the Danish Viking king Harald Bluetooth lost control of the Danevirke and parts of Southern Jutland to the Germans. The entire complex of fortifications, bridges and roads which were built around 980 are presumed to be Harald’s work, and part of a larger defensive system.
Another theory is that the ring castles were boot camps for the troops used by Sweyn Forkbeard in his attack on England. Sweyn and his men sacked London in 1013.
