|and here she is, looking relaxed, a Victorian icon, Whistler's Mother Anna|
Wikimedia Commons, Public Domain
Although - it wasn't quite like that. There is a backstory. An MP had asked Whistler to paint his daughter Maggie Graham, according to mentalfloss.com. It appears Maggie got fed up, and so Whistler was left with a prepared canvass doing nothing.
So his asked his Mum to sit in. The result has been described as iconic as the Mona Lisa.
The ironic thing about this painting is that it was almost rejected by the Royal Academy in 1872, but ended up being widely admired and feted worldwide, which must have been very satisfying for the artist. Its permanent home, when it's not touring is in the Musee D'Orsay in Paris, France.
Whistler's Wikipedia page quotes the artist after his painting began to attracted attention::