It is an amalgamation of many different traditions and some may even contradicts others... The common ground that makes it Hinduism is the Quest to actualize and become who we truly are...
This said, Siddartha was of royal heritage, thus higher cast, thus from the Bhramanic "religion" which is part of what we now call Hinduism
The foundation of Buddhism is based on some Hindu fundamentals... very closely linked to Vedanta...
Buddhism is to Hinduism, what Christianity is to Jewdism...
It was a liberating force from the grip of the Brahmani Cast system... It appeal to lower cast and women until it was totally destroyed by Muslim invasions and genocide of Northen India...
Yes. Nice story to read, really. He walked the Earth five centuries before Yeshua [Jesus Christ] did and they both share similar stories of fasting for forty days and forty nights, and then choosing their twelve disciples, if I'm not mistaken.
"Siddhartha" is still required reading for High School, right?
Yes
Gautama Buddha was born "Siddhartha" in the year 563 B.C. to King Suddhodan & Maya Devi in the village of Lumbini near Kapila Vastu, within the present borders of Nepal.
He studied and practiced Hindu discipline initially, and then, Jainism... he then took the middle path... which eventually led to his enlightenment in Gayla
Siddhartha Gautama, the historical Buddha was born into a Hindu family. He even had an arranged marriage. When he left his family and the trappings of luxury at age 29, he studied many aspects of Hinduism including Yoga and Brahmin meditation. He spent time as a Hindu mendicant monk and later a ascetic monk while practicing vigorous techniques of physical and mental austerity. It is said that Siddhartha Gautama was adept at these practices and was even able to surpass many of his teachers. However, finding no answers to his questions and no end to suffering, he sat under a pi pal tree and vowed not to rise until he found the truth. It was at this time that he reached enlightenment and started teaching what is today called Buddhism.