Fortress ring

The term fortress ring or fortress belt denotes:

• the ring that the towers and walls of a circular fortress form around a city or castle (for example, the city of Cologne was surrounded by a double fortress ring under Prussian administration (since 1815) ), see Cologne fortress ring

• a ring of forts that lie around a city, to protect them from Artilliebeschuss and make it difficult to besieging the city - see for example Fortified Position of Liège , Warsaw Fortress (19th century) , fortress Maubeuge , Fortress Ring Cologne , Fort belt around Ingolstadt

• in a broader sense, a line of fortresses is sometimes referred to as a 'fortification ring'; this even if the fortresses do not form a complete circle. For example, after the lost war of 1870/71 , France built one such line, the Barrière de fer . Its northern part protected large parts of northern and central France as a 'fortress ring' until it became obsolete from around 1890 due to the emerging explosive shells and higher firing ranges of the artillery .

This is a disambiguation page for differentiating between several terms identified with the same word.