There was a simple reason for this. Jacques was a prince. He hatched, slightly before his brother, who was dubbed Louis. However, as far as the world was concerned, Louis was the firstborn. The fact that Jacques was the first to spill forth from his shell was hidden from the rest of the world for one simple reason: Jacques was born with vestigial wings, whereas his brother was born with a set destined to develop fully. The birth certificates were altered, Louis was named heir, and days after birth, Jacques's vestigial wings were surgically removed so that it could be claimed he was a wingless, and not one of the "mutants".
Jacques's early life was as decked in gold, jewels, and attention as his birth had been. As his parents, Queen Isabelle and King Louis VII, were the high monarchs of Atlian, there was much room to lavish their sons in attention. Of course, Jacques always got the short end of the gold and jewel encrusted stick, as his brother was heir, and was developing a beautiful set of wings. Jacques, although bright and inventive, was also mildly eccentric and peculiar in personality, and was outshone by his brother's natural charisma. It was a competition. Both were equal in faults and strengths. Jacques was intuitive, intelligent, and witty, while mildly antisocial and temperamental. Louis was charming, charismatic, and dedicated, yet still he lacked his brother's remarkable intelligence and foresight. In the end, it was as it had been from the beginning: the ability to fly would be what determined the kingship more than order of birth. Kings had wings, and it had always been that way since the winged Volares overtook and consumed the wingless Apteryx society.
The unfairness of their birth was kept a mystery to the two brothers, thus, they were able to get along fairly well. There was some resentment among Louis and the slightly larger Jacques, due to small envies and natural sibling tryst, but on the deeper level they were close friends. Twins, after all, have a natural tendency to look to each other. Often, between lessons, the two would slip away to play in the spaces between. It all worked well, until Louis reached adolescence.