The formality of your wedding ceremony, the time of day and the season, will determine what type of wedding attire your Prince and his groomsmen will wear. You should start looking for men's formalwear about 2-6 months in advance.
Coordination is what counts.
It is a good idea to bring along swatches of material from the bridesmaids dresses and try to match them to the men's formalwear. There is an awesome selection of styles and colors available to today's groom and his party. From pleated pants and continental jackets to a top hat and tails and designer name tuxes as well. It is important that the groom chooses a tux that is compatible with the color scheme rest of the wedding party. It is a good idea to try on the tux after alterations have been made a week or two before the wedding.