The campus transports visitors through time. Nestled on 1,600 acres in England’s bucolic Berkshire countryside just a few minutes’ drive from Windsor Castle, the nearly 600-year-old Eton College remains one of Britain’s most exclusive and prestigious all-boys educational institutions for 13- to 18-year-olds. In June, Prince George and his parents, Prince William and Princess Kate, paid a visit to the Prince of Wales’ alma mater — which was also attended by Prince Harry and Hollywood stars including Tom Hiddleston, Eddie Redmayne and Bear Grylls. But in October, Kate was spotted an hour away visiting a different esteemed school studded with centuries-old brick buildings: her alma mater, the coed Marlborough College.

A huge decision has been looming. Though students don’t attend either institution until they’re teenagers, enrollment is determined the year they turn 10. “After years of discussion and heated debates between William, Kate and King Charles III, the family have made a choice,” says a royals source. Rather than send George, 10, away on his own, “they’ve decided that he and sister Charlotte will attend boarding school together. While the royal family expected that George would follow in William’s footsteps, Kate got the final say: They’ll both be students at Marlborough. This way, George and Charlotte will have a few years where they’ll overlap at the same school. Kate has fond memories of her time there and feels it’s a better fit for her children.”

She knows just how important it is to find the right fit. Kate, herself, reportedly ended up at Marlborough after being bullied out of a previous school. William, 41, “is happy for Kate to take the lead,” shares another insider, “because he doesn’t like fighting with his father.”

Indeed, Charles, 75, is all about tradition. After he, his brothers and late father Prince Philip each attended Gordonstoun, an elite boarding school in Scotland, the monarch sent his own sons away to be educated when they were just 8. But Kate, 41, has al- ready bucked that tradition, enrolling George, Charlotte, 8, and youngest son Louis, 5, at the $30,000-a-year coed Lambrook school, near her and William’s new home in Windsor after moving from London. “Kate’s always wanted them to have more of a normal upbringing than William did,” explains the source, noting Kate’s latest victory in the boarding school saga “is a big step and one that came with many tense conversations.”

The Princess of Wales doesn’t compromise when it comes to her kids. “She knows full well that in a few short years, George’s life is going to drastically change” as he takes on more responsibilities as the heir to the throne, says the insider, and “thinks he shouldn’t be torn away from his family.”

Aside from eventually having Charlotte by his side, George will be only about an hour’s drive away from the Cambridges’ abode once he’s settled in at Marlborough. “It’s not terribly far from home,” confirms the source, “and Kate will be able to easily visit her kids.”