Was Buddhism a rebellion against the Aryans? I read and learned many areas in Buddhism, for example the Seven Arya Dhana (Saptharyadhana - The Sevenfold Noble Wealth), the Four Noble Truths (Chathurarya Sathya) and the Eightfold Path (arya ashtangika marga). 

I sometimes feel in the time when Gautama was born, the Aryans had ultimate power because of the caste system. So Gautama needed to break that authority and misbehave and tell people that this is the way to be an Aryan (and not by family birth in the caste system). 

I admit that the teaching of [how to live] life is the basis of Buddhism. But rather than that i feel that there are some other things. 

(Sorry about the Sinhalese wordings. I don't know how to say it in English. Please correct if you know the exact English words). 

This is not a theory or something. This is something i feel when I am learning the philosophy. 

Thank you.
When Gautama left his family to become an ascetic or śramaṇa, he joined many other ascetics or wanderers who were separate from the Vedic-Brahmanism religion. 

However, when Gautama left his family to become an ascetic, his goal was not political. The Pali scriptures describe when Gautama lived the life of a prince in his palaces, he was very unhappy &amp; disenchanted &amp; also saw how his rich relatives &amp; associates suffered about worldly things, such as money, status, sex &amp; sensuality, which brought little happiness &amp; much trouble &amp; suffering.   

Therefore, Gautama became an ascetic for the sole purpose of finding a solution to suffering for himself &amp; for the world. Gautama's sole purpose was a Noble Search for Nibbana.

Later, after enlightenment, when the Buddha became famous, the scriptures report many Brahmans ('Aryans') came to visit the Buddha to ask him questions about 'caste' or 'birth' ('jati').   

Because the Buddha was an honest &amp; ethical man, he spoke the truth to the Brahmans (for example, here, here and here. 

In Singala: https://suttacentral.net/si/mn93 ~ https://suttacentral.net/si/mn95
~ https://suttacentral.net/si/mn98

Because the Buddha &amp; many of his enlightened disciples were not from the Brahman caste, the Buddha understood with right wisdom that the highest, most peaceful, wise, virtuous &amp; free state of mind was not related to birth caste (read Brahmanavagga). 

I would speculate that hundreds of years later, under King Ashoka, many new scriptures were written that were very prejudiced against Brahmans (such as here &amp; here). 

I say this because in many scriptures, the Buddha is very civil to Brahmans and encouraged them to follow their own religion in a better way. The Buddha did not try to convert anyone to Buddhism unless he knew Buddhism was the most suitable path for that person.