Gregory told the guard with the register their visitors name and confirmed that yes, he was a messenger from Trabia. General messenger, not royal or military.
Gregory didn't know what a flight was but it sounded like something that needed to be organized. "We are most grateful for all the Trabian soldiers. Please, follow me with the letters."
Delivering these were going to be a big task, and the messenger was probably exhausted. Gregory helped him carry his letter bags to their waiting parlor just inside the castle and left him there to wait.
After a few minutes Cid came in to greet him. Cid of course spoke all four languages. The royal master of the house had to. He greeted the messenger and introduced himself. Explained to him that they took care of his horse and were setting him up a room to stay in, however many days he wanted to rest.
Hollow Bastion was known for hospitality so of course Cid wasn't gonna have HIM deliver all these letters. Not when he could have the Flight leaders rounded up to come retrieve them instead. "You're just in time for lunch."
Thus one of the servants was off to find Corin to summon him to the parlor to pick up the letters for his flight.
And the servant that brought the snack tray (small, since it was about lunch time) for the Prince knocked on the stall. "Your Majesty, your tray. As well you might like to know, it seems a Trabian messenger just arrived at the castle." Didn't know what for, but someone had just brought his horse in.