The aim of meditation is ultimately, in either a small or grand way, to reduce suffering. All human beings experience negative emotions or thoughts, the root cause of which will usually lay somewhere in the mind. In order to end suffering these must be overcome. These aspects of the mind are often symbolised in Buddhism as ‘Mara’, a being bent on creating fear, desire and doubt, or ignorance, in his victims.
At the point of his enlightenment the Buddha famously overcame Mara’s monsters, then his daughters, then Mara and his criticism himself.
Here is a short quote from a talk called ‘The Buddha’s Victory’ by Sangharakshita. The full talk is available as audio or text at the link at the bottom:
“Victory usually implies victory over someone or something. Who or what, then, could this have been in the Buddha’s case? The answer is simple: the Buddha conquered Mara, the `Evil One’, and after conquering Mara, attained Enlightenment. In a sense, his conquest of Mara, his Mara-vijaya as it is called, was his attainment of Enlightenment.
It is possible that you have already encountered descriptions of the episode of the conquest of Mara. Perhaps you have seen it depicted in Buddhist art. If so, you will have seen the Buddha-to-be sitting on a heap of kusa grass beneath the spreading branches of the ficus religiosus, or sacred fig tree–subsequently known, in honour of the Buddha, as the Bodhi tree, or `tree of Enlightenment’. He is surrounded on all sides by thousands of fearsome figures, all horribly misshapen and deformed. Some of them are whirling enormous clubs, some are spitting fire; some are in the act of hurling great rocks, even whole mountains that they have torn up by the roots; some again are discharging arrows. These are the forces of Mara. Mara himself stands to one side directing his terrible army in its onslaught on the Buddha. But the Buddha himself takes no notice. He is completely surrounded by an aura of golden light. As soon as the various missiles touch this aura they turn into flowers and fall to the ground at the Buddha’s feet as though in unintentional worship. The Buddha is undisturbed and carries on meditating. He does not take any notice even when Mara summons his three daughters and orders them to dance in the most seductive manner. So Mara retires defeated, his forces disappear, and his three daughters withdraw in confusion. The Buddha is left alone beneath the Bodhi tree on his heap of kusa grass, and carries on meditating. Sitting there in that way he attains Enlightenment.”