Why did Richard III lose the Battle of Bosworth?

Henry, knowing himself to be not very experienced in leading battles, delegated this responsibilty to the earl of Oxford who kept the majority of this outnumbered army together.
Richard split his army into several smaller groups but they struggled to cause great effect against Henry's army, with many soldiers fleeing the battle.
In a desperate attempt to end the battle quicker, Richard led his own group charging into the fray in an attempt to end the battle quickly by piercing Henry's army and killing him. At this point Stanley led his men into battle to fight against Richard's men, believing that Henry was more likely to succeed in this battle. Outnumbered and outmatched, Richard's army was slain and so was Richard.