Who sat under a tree for 40 days and 40 nights?

The figure who sat under a tree for 40 days and 40 nights is Siddhartha Gautama, known as the Buddha. According to Buddhist tradition, he meditated under the Bodhi tree in Bodh Gaya, India, during this period, seeking enlightenment. After this time of deep contemplation, he attained enlightenment and became the Buddha, teaching the path to liberation from suffering.