That’s a tough question…there are so many ways to go with this! Here’s my try:
Buddhism is the teachings and spiritual practices accomplished, brought forth and instructed by the Buddha in around 2500 BCE. Siddhartha Gautama, later the Buddha, perceived that there was unsatisfactoriness and suffering in pursuing that which is subject to subject to decay and death and so set out to discover for himself that which was not subject to decay and death. His teachings mirror his own personal journey that he ultimately cultivated in order to to fully see what suffering is, it’s arising, it’s passing and the path out of it. Through a diligent, meticulous and exhaustive examination of each facet of his mental and physical experience of life, he broke through his subjective conditioned presumptions that his mind had fabricated about body, feeling tones, perceptions, and consciousness. Through pure ethical conduct, deep meditation and contemplation and with profound wisdom, he encountered and removed all hinderances and impurities of his mind to ultimately dispel his ignorance, misperceptions and craving. After eliminating the source of all suffering for himself, he spent the remaining 40 years of his life in the bliss of peace, instructing and guiding others. Buddhism is based upon thousands of suttas, or sermons, given by the Buddha and preserved first orally and later written in a variety of cultures and languages. Over time, slight differences of interpretation and practices have given rise to different schools and traditions of Buddhism.