Kate Middleton, apparently, had a "very strategic" plan to become Prince William's wife when she was 19 years old. Royal biographer Robert Lacey, the author of Battle of Brothers, detailed what the Duchess of Cambridge did to end up with the future King of the United Kingdom.

According to Lacey, Kate wasn't supposed to attend St. Andrews University, where she and Prince William met. She was accepted at another premier university but, allegedly, gave up her slot when she found out that the royal was going to study in St. Andrews.

Kate was done sorting out her accommodations in Edinburgh when she decided to switch schools, as well as switch courses. The Duchess of Cambridge took art history to be in the same classes as Prince William in 2001. Attendance at St. Andrew, apparently, increased to 44 percent the year Prince William started his university studies.

The pair, however, didn't begin dating right away though they met in their very first semester. Prince William took notice and became widely smitten with Kate after seeing her in a see-through dress during a school charity fashion show.

Prince William, however, wasn't Kate's first love. A friend revealed to Daily Mail that the duchess was hung up on a guy named Harry Blakelock, who was her former schoolmate at Marlborough College.

Harry was the hockey captain and their relationship was hot and cold. The friend said that Kate couldn't stop talking about Harry when they spent their gap year in Florence, Italy.

This belied Lacey's claims that Kate had her eye on William even before they actually met. A friend also said that Kate decided to go to St. Andrews because it's traditionally where graduates of Marlborough go. Most of her friends from her old school are going to be at the same university.

Meanwhile, in their second year at St. Andrews, Kate and William's friendship slowly blossomed into romance. The Duke of Cambridge decided to move into the same flat as his future bride, along with their other friends.

In 2004, photos of William and Kate started appearing in the tabloids. A few months later, friends confirmed that they are an item but Clarence House never made comments on the reports.

In 2005, William and Kate both graduated from St. Andrews and their family celebrated together by having lunch. According to Hello!, this seemed to confirm that Kate was ready to become a permanent part of the future king's life.

The pair broke up in 2007 only to reunite the following year. By the fall of 2010, Prince William proposed to Kate but they didn't make this public until November. This month marks the 10 years since Kate and William announced their engagement to the world.