After winning the Battle of Poitiers, Karl Martell conquered the south of France from the Arabs, but did not go beyond the Pyrenees. At the end of the 8th century, Charlemagne did this, but did not have much success. Why?
The people of the Iberian Peninsula (descendants of the Basques and Visigoths) considered the northern Franks as invaders as the southern Arabs and Berbers, and fiercely resisted.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.