The Knights of Hydrogia attending the banquet were given instruction to go through the back of the castle, the same way they went when attending practice in the palace.
With all the carriages of nobles visiting the castle for the banquet and the pathway filled with servants attending to the horses, it was too crowded for the knights to arrive in that manner.
Since Henry was a guest of the princess, he was going to meet the princess in one of the sitting rooms and enjoy tea with her before it was time for her to arrive in the Great Hall. The king and Crown Prince were the only ones required to greet guests at the front door.
Logan and Arthur made themselves sarce quickly, servants bringing them to where they would enjoy their meal for that evening. Commander Lothian was more hesitant to part with Henry and one of his eyebrows raised as Henry excused himself to the designated meeting room where the servant was guiding him to.