The battle started with a French bombardment. This caused the Allies to retire behind a fold in the ground.
The French then launched a succession of piecemeal attacks on the Allied lines, but none with enough strength to break through.
The Brunswick artillery repulsed the first infantry attack.
The Duke of Brunswick was in the thick of things, but unhistrionically survived to fight again at Waterloo.
Reinforcements: The Guards arrive! At about the same time, Wellington turned up and helped rally many inexperienced recruits back to the colours!
And the French didn't have enough reserves to push any more. D'Erlon never turned up! The Allies held the crossroads.