The estranged families joined a united front for a walk outside Windsor Castle at the weekend, where they thanked the crowds who gathered there to express their sympathy and saw piles of flowers and balloons left behind. However, the show of unity required “extensive behind-the-scenes negotiations beforehand”, which then delayed their arrival for the walk by 45 minutes, according to the Times of London. Prince William, the newly appointed Prince of Wales and heir to the throne, was the one who put out the olive branch before the reunion. “The Prince of Wales has invited the Duke and Duchess to join him and the Princess of Wales,” a spokesman for Prince William said in a statement to the agency. The unity show required “extensive behind-the-scenes negotiations in advance” which then delayed their arrival by 45 minutes. Kirsty O’Connor/Pool/AFP via Getty Images Princes William and Harry, along with their wives Kate and Meghan, view flowers and tributes to Queen Elizabeth. Chris Jackson/Getty Images Floral tributes surround a photo of Queen Elizabeth. Scott Heppell/AP “The Prince of Wales thought it was an important show of unity at an incredibly difficult time for the family.” Find out about the death of Queen Elizabeth II with The Post’s live coverage The crowd rejoiced at the sight of the two brothers being side by side again. The siblings and their wives, Kate Middleton and Meghan Markle, then spent nearly an hour shaking hands, accepting flowers and talking at length to royal fans who had waited hours in hopes of getting a glimpse. Prince William was reportedly the one to put out the olive branch before the reunion. Andrew Couldridge/REUTERS The reunion came after their father, King Charles III, reportedly banned Markle from meeting other family members at the Queen’s bedside at Balmoral before he died on Thursday. Charles “made it very, very clear that Meghan would not be welcome,” a royal source told The Sun. The outing was the couple’s first public appearance since Commonwealth Day on March 9 amid their ongoing feud.