The Queen had "reached her limit" with the Duchesses - formerly known as Meghan Markle and Kate Middleton - according to reports from the US.
A source told Us Weekly the Queen was fearful for the overall relationship of the Royal Family and is glad both Duchesses put their differences aside.
Kate and Meghan recently put on a friendly display as they arrived for a Christmas Day church service at Sandringham, with a source revealing the Queen "desperately wanted Meghan and Kate to make up and she got her wish."
As the royals gathered at the Queen's home in Sandringham for the Christmas period, the source said: "Being under the same roof meant that they couldn't avoid each other."
According to The Sun, Kate and Meghan enjoyed a game of Scrabble together.
"After watching the Queen's speech, the board games were brought out and both women got stuck in," an insider told The Sun
"They were chuckling along together. You wouldn't know there was any tension between the two. It was a wonderful day and night."
Rumours of the pair's rift began to circulate late in 2018 when royal sources claimed Kate was "left in tears" over Meghan's strict demands for Princess Charlotte's bridesmaid dress.
A royal insider also claims there is tension between brothers Prince Harry and Prince William, who now reportedly don't want to live next to each other.
Speaking on the decision to move homes, a royal source told The Sun, "The initial plan was for Harry and Meghan to move out of their cottage in the grounds of Kensington Palace and into one of the main apartments.
"But there has been a bit of tension between the brothers.
"Now Harry and Meghan don't want to live next to William and Kate and want to strike out on their own."
It is understood they want to bring up a family away from the "goldfish bowl" of London and live a more private life.