Charles Spencer has educated his legions of fans over the years with insights into the Althorp estate, where Princess Diana grew up.
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The Earl often shares photos of the grand manor in the morning mist or at other scenic times of the day, and he also shows inside the 90-room house. During the week, he gave a peek inside one that was called the Sunderland Room, and it contained a desk where a small lampshade stood, surrounded by a holly wreath.
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A portrait of a bull and one of Charles' relatives hung on a wall that had been decorated with an ornate red wallpaper.
Sharing insights into the room, he explained: "The Sunderland Room, in festive spirit- with a portrait behind of 'Honest Jack' Spencer, the 3rd Earl, with one of his prize shorthorn bulls.
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"After the loss of his wife and their only baby in childbirth, he devoted his energies to agriculture, especially his herd of shorthorns. He never remarried, and was succeeded by his younger brother Frederick."
However, one thing the father-of-seven didn't explain was how the room got its name, and this intrigued many fans.
The Earl gave a look inside the room
"Why is it called the Sunderland room?" questioned one, while a second pondered: "I wonder how it got its name."
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Many others thanked the Earl for sharing the "bittersweet" story and expressed their sympathies for the situation that his late relative found himself in.
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Charles will have had an extravagant Christmas, and he wowed his followers ahead of the festive season with his jaw-dropping Christmas tree.
Adorned with twinkling lights and red baubles, the tree was the focal point of the hallway and was so tall it could be reached from the second floor.
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Placed in front of a marble and gold fireplace, portraits of the Spencer family ancestors adorn the walls behind the Christmas tree.
"Wishing you all a very Happy Christmas / Happy Holidays!" Charles wrote in the post.