My sister Amy wanted an outdoor wedding ... in late September, in Pennsylvania. She and her fiancé decided to hold the reception at a local state park picnic pavilion with outhouses for bathrooms. Despite protests from both sides of the family, the engaged couple prevailed, and on the wedding day, there we were, shivering in the nippy fall air with ski jackets over our bridesmaid dresses.

Bucking tradition in a regular family is tough enough, but when you're marrying the future king of England, you have to choose any departure from royal rituals very carefully.

All in all, Kate and William are not throwing custom out the window with their personal wedding choices. They'll have the traditional wedding fruitcake, but also a chocolate biscuit cake requested by William. They're getting married before noon, the traditional time slot, but instead of a wedding breakfast, they're having a canapé and champagne reception. They won't leave for their honeymoon the afternoon of the wedding like most royals do, but will stay for a "hip" evening party hosted by Prince Charles (though using the word "hip" in the same sentence as "Prince Charles" is quite a stretch.)

But William and Kate's engagement broke the oldest mandates of monarchy matches: Royals marry royals, or people connected to royals. Technically, to be a royal, you have to be directly connected to a titled Brit or royal family of another country. Prince Phillip, grandfather of William and husband of the Queen of England, is a descendant of Queen Victoria. Diana's father was the Earl of Spencer; thus, Diana was Lady Diana Spencer (she even had her own family tiara and didn't have to borrow one from the Queen). And Camilla, despite the less flattering names the Brits have called her, is the granddaughter of a Baron.

Kate Middleton is a true "commoner." She comes from a middle-class background whose ancestors were coal miners, not aristocrats. She'll be the first non-royal in centuries to marry a future king. Her mother and father operate an Internet children's party store, which even sells a "Princess Party Kit."

While most people know of Anne Boleyn as one of Henry the Eighth's short-term wives, she too was a commoner with no connections at all to nobility. King Edward left the throne to marry the American divorcee Wallis Simpson. In Britain, the Royal Marriages Act of 1772 mandates that all royal descendants who want to get married seek approval from the sitting monarch.

Obviously, the Queen approved of Will and Kate's marriage, which she said she's "delighted" about. She even finally, after eight years, invited the Middletons to Buckingham Palace for lunch.

William and Kate's wedding will be at Westminster Abbey, the location of most royal weddings. William's parents broke with tradition and got married at St. Paul's Cathedral due to the large guest list, but Charles and Camilla got married at the original royal wedding venue, the Chapel Royal at St. James Palace, because of the small guest list (or lack of RSVPs).

Kate and William made no unusual requests for changes in the actual ceremony. It's anticipated to be a traditional aristocratic wedding, and will follow standard decorum for weddings in the Abbey. The couple won't kiss at the end of the ceremony, Kate won't toss her bouquet into the throng of wannabe princesses outside the Abbey and don't expect to see Elton John at the piano with a microphone.

Speaking of Kate's bouquet, she'll leave it at the Tomb of the Unknown Soldier inside the Abbey, a tradition started by William's great-grandmother Elizabeth Bowes-Lyon. What flowers will be in it is a royal secret, but she will have a sprig of myrtle, a tradition that began with Queen Victoria and which all royal brides, including Princess Diana, have followed since.

While the entire world anxiously waits to see Kate's wedding dress, one royal tradition she won't break with is the color. In the 16th century, Queen Victoria daringly bucked the tradition of royal brides wearing silver wedding gowns by appearing in a color considered shocking at the time: white. All royal English brides have followed suit ever since.

Royal wedding rings have been made from the same nugget of Welsh gold since 1923, and even though there's not much of it left, Kate's ring will be no exception. But scarce Welsh gold isn't the reason William won't have a ring -- he is following the royal tradition of men not wearing them (he's also said to have decided he's not the jewelry type). His father didn't wear a ring when he married his mother, but decided to change with the times and get one for his marriage to Camilla.

Perhaps the most admirable break from royal tradition is the couple's decision to replace gifts with donations to charity. Kate and Will compiled a list of 26 organizations for well-wishers to donate to in lieu of presents they don't need.

As for a wedding tradition all brides observe -- something old, something new, something borrowed, something blue -- who knows what Kate will do? You can bet, at least, that her tiara will be borrowed from the Queen and not from the Princess Party Kit sold by her parents.

Patti Lawson is an award-winning author and columnist who lives in Charleston, West Virginia. Her first book, "The Dog Diet, A Memoir," is the story of her beloved adopted canine companion, Sadie. A lawyer by day, she is completing a book for women lawyers and a legal guide for dog owners. To buy Patti's books and to learn more about her, visit Red Room.