In the example of a Welsh siege, Hawarden had to be taken quickly. Otherwise, English troops could sail along the coast to Flint and reach the besiegers on foot or horseback. Arrival on a night tide would allow disembarkation and a march in darkness, so the first warning might be the attack itself. Besieging Flint presented a different difficulty: roads and bridges from England provided overland routes for reinforcements. Those routes were difficult to block completely. The position of the two castles therefore gave relieving forces several ways to reach a siege.
Notable Point · 8:26-9:30
Night tides and relief of a siege at Hawarden
A prolonged siege of Hawarden risked a surprise attack by troops landed at Flint; Flint could also receive reinforcements along roads and bridges from England.