The Ring of Iron(Nee Stone): Flint Castle - Long Patrol P4/14

Flint's unusual plan places a separate great tower beside the entrance, with defended wards and ship access from the tidal River Dee.

Successive drawbridges force attackers through open ground and close combat while archers in the great tower keep firing into their route.

Richard the Engineer began Flint's construction; James of St George took over for seventeen months before moving to Rhuddlan. A wall protected its harbour.

Flint's stated £6,000 construction cost prompts a tentative comparison between a £5.4 million modern equivalent and a larger burden measured against government spending.

Flint is paired with Shotwick Castle across the Dee, making any siege harder because another garrison could reinforce the river-side position.

Flint's detached great tower combines exceptionally thick walls with a separate drawbridge and access to supplies by sea.

A wooden gallery gave the future Edward II more room in the great tower during his 1301 visit.

Flint began Edward I's Ring of Iron in 1277, with the decision to build backed by the army he brought to the site.

Two Welsh attacks test Flint's defences, with a failed 1282 siege followed by the constable burning vulnerable outer areas during the revolt of 1294.

Flint holds Richard II for Henry Bolingbroke in 1399 and remains defensible enough to sustain a three-month Civil War siege in 1647.

Flint's outer bailey became part of Flintshire's county jail, with quarrying nearby. Its naval namesake was a Second World War Castle-class corvette.

Edward I's opponents in Gwynedd and Snowdonia explain the choice of a northern approach, even though southern Wales was richer and easier for his forces to reach.