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The portrait of the Fat Lady seems to have been painted at the time of the Renaissance, and depicts a noble Greek woman, though none are sure of her actual identity. From the Fat Lady’s attitude, she was probably a Dionysian (i.e. a follower of Dionysus, the Greek god of wine, ecstasy, and ritual madness). It is believed that the woman’s family donated the portrait to Hogwarts due to the castle holding many other famous paintings.

It is unknown where the portrait of the Fat Lady was placed before she began guarding Gryffindor Tower in 1960, or who guarded it before her. She is a very flamboyant woman who loves to get drunk, be merry, and gossip with her best friend Violet. The two women often get incredibly drunk around Christmas break, consuming several of the monk portrait’s never ending vats. The Fat Lady will often scold students for waking her from her beauty sleep as they return late to the Tower.

In 1993, the Fat Lady’s portrait was shredded by Sirius Black because she refused to let him enter without the password. Filch worked hard to restore the portrait, during which time she was replaced temporarily by Sir Cadogan. When asked to return she refused to be the guard again without some sort of security, so two security trolls were stationed in the hallway by her portrait.