In 2010, a Boldini portrait was found in a Paris flat that had been sealed for over fifty years. The painting showed his former muse, the actress Marthe de Florian, and it emerged into a world that had largely forgotten both the sitter and the scale of Boldini's fame. In the 1890s he had been the most fashionable portrait painter in Paris, with a waiting list that included aristocrats, actresses and anyone who wanted to look more alive than they actually were.

He was born in Ferrara in 1842, the son of a painter. He was filling sketchbooks by the age of five, before he could write. At eighteen he already had a reputation as a portraitist. In 1862 he went to Florence and fell in with the Macchiaioli, the Italian precursors to Impressionism whose broken brushwork and plein-air practice influenced his early style. He reached Paris in 1871 and stayed.

Time magazine later called him the "Master of Swish" for his fluid, elongated brushstrokes. His portraits captured sitters in soft focus, stretching their features to accentuate elegance and creating a sense of motion that made his subjects look both sophisticated and restless. The technique owed something to Parmigianino's Mannerist elongations and anticipated Futurism's interest in movement. He was friends with Degas, Manet, Sisley, Caillebotte and Corot, and in 1889 travelled to Spain with Degas to study Velazquez and Goya.

He worked in oil, pastel, watercolour and drawing, and was prolific across all media. He died in Paris in 1931, at eighty-eight, having outlived Belle Epoque society and the world that had kept him busy.