Charlemagne was the first Frankish ruler to believe in what for all people

The correct answer is Education.

Charlemagne was the first Frankish ruler to believe that all people who have the right to a good education.

Explanation:

Charlemagne had a lot of contact with Moorish as well as Anglo-Saxon cultures. The Moorish, being the most advanced society in Europe, greatly inspired him to work on educational reforms for his won people.

He supported monasteries, scholars and encouraged translation of books. This also lead to the development of private libraries and a keen interest by the common man to learn music, religion, history and poetry.