Why at the beginning of the 5th century BC Darius the First decided to conquer Hellas?

At the beginning of the 5th century BC   King Darius the First decided to subjugate Hellas, since the Persian nobility strove for new conquests, for new lands and riches.

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.