Turret (Hadrian's Wall)

A turret was a small watch tower, incorporated into the curtain wall of Hadrian's Wall. The turrets were normally spaced at intervals of one third of a Roman mile (equivalent to 495 metres (541 yd)) between Milecastles, giving two Turrets between each Milecastle.

In the numbering system introduced by J. Collingwood Bruce in 1930, Turrets were numbered after the Milecastle located to the east of the turret. The nearest turret to the milecastle is suffixed by 'A', and the other turret by 'B'. For example, travelling west from Milecastle 33, the first Turret encountered would be Turret 33A, and the second would be Turret 33B. Both lower and upper case 'A' and 'B' suffixes are in widespread use, and the full name is often abbreviated to (for example) 'T33a'.

Many turrets also have a name, which is often shown in brackets following the number. For example, Brunton Turret is often referred to as 'Turret 26B (Brunton)'.

Where the Turf Wall and Stone Walls diverge from one another (just to the east of Birdoswald), Milecastles and Turrets unique to the Turf Wall are given a 'TW' suffix, for example 'T50bTW'. A suffix of 'SW' may also be used to uniquely identify a turret as belonging to the 'Stone Wall'.

Although Hadrian's Wall itself ended (at its western terminus) just beyond the fort of Maia at the modern village of Bowness-on-Solway on the Cumbrian coast, the system of milecastles and turrets continued beyond this point, as far as Flimby, with comparable spacing. However, the nomenclature adopted for the Milecastle equivalent is 'Milefortlet', and the equivalent of the turret is a Tower. The numbering system adopted for the towers along the Cumbrian Coast is (for example) 'T21a CC' (the 'CC' suffix meaning 'Cumbrian Coast'), though the CC suffix is often not used if the reference is clear from the context, so care must be taken not to confuse (for example) 'T21a' meaning 'Turret 21a', and 'T21a' meaning 'Tower 21a'.

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