Battle of Thielt (or Hackespol), 21 June 1128 (Flanders)
Battle fought over the succession to the county of Flanders between Dietrich, count of Elsass and William the Clito, son of Duke Robert of Normandy. Neither side had any infantry, and the battle was decided by William's clever use of his reserve. Both sides split their forces into three lines of battles, but William kept his third line hidden. Soon, the first two lines on each side were engaged, and Dietrich, thinking William's entire army was engaged, moved his reserve into the fray. William's men were forced to retire, but at that point his reserve charged into the battle, to the surprise of Dietrich's forces. William was able to use the respite to rally some of the first lines and re-entered the battle, scattering Dietrich's forces. William seemed established as count of Flanders, but only two months later he died of blood poisoning caused by a scratch in the hand, and Dietrich was able to claim the county unopposed.
How to cite this article:
Rickard, J. (19 October 2000), Battle of Thielt (or Hackespol), 21 June 1128, http://www.historyofwar.org/articles/battles_thielt.html