Pippa Middleton's wedding wasn't technically royal, but there were still princes there ... along with tennis royalty.

Several members of the Royal Family -- including Prince William and Prince Harry -- arrived at St. Mark's Church Saturday to see Pippa -- sister of Catherine, Duchess of Cambridge -- walk down the aisle and marry hedge fund manager James Matthews.

The church is a 12th-century church just a couple of miles away from her parent's home in Englefield, Berkshire. The ceremony is believed to have cost over £250,000.