Flint formed part of a cross-river system with Shotwick Castle on the English shore. Shotwick had been the more important position before Flint was built. Although its importance then declined, it remained Flint's backing or redoubt point during the new castle's early service. A besieger without ships could not easily deal with both banks of the Dee. Leaving Shotwick alone allowed its garrison to reinforce Flint across the river.
Notable Point · 6:25-7:36
Shotwick and cross-Dee relief
Flint is paired with Shotwick Castle across the Dee, making any siege harder because another garrison could reinforce the river-side position.