Mona Lisa
Today the "Mona Lisa" is considered the most famous painting in the world, but until the 20th century it was simply one among many highly regarded artworks.
Once part of King Francis I of France's collection, the "Mona Lisa" was among the first artworks to be exhibited in Louvre, which became a national museum after the French Revolution. From the 19th century Leonardo began to be revered as a genius and the painting's popularity grew from the mid-19th century when French intelligentsia developed a theme that it was mysterious and a representation of the femme fatale.
The Baedeker guide in 1878 called it "the most celebrated work of Leonardo in the Louvre", but the painting was known more by the intelligentsia than the general public.
The 1911 theft of the "Mona Lisa" and its subsequent return was reported worldwide, leading to a massive increase in public recognition of the painting. During the 20th century it was an object for mass reproduction, merchandising, lampooning and speculation, and was claimed to have been reproduced in "300 paintings and 2,000 advertisements". It has been said that the "Mona Lisa" was regarded as "just another Leonardo until early last century, when the scandal of the painting's theft from the Louvre and subsequent return kept a spotlight on it over several years."
Portrait of Dorothea Berck
Portrait of Dorothea Berck is a 1644 painting by Frans Hals that is in the collection of the Baltimore Museum of Art. It depicts Dorothea Berck at age 51, the wife of the prosperous Haarlem merchant Joseph Coymans, whose portrait Hals also painted. Both paintings were executed on the occasion of their daughter Isabella's wedding, whose marriage pendants Hals also painted.
The painting, like many of Hals's portraits, is inscribed and signed, but there is no mention of the identity of the sitter, and it was only identified as Berck in 1908. 
The portrait is noted for its classical similarity to the Mona Lisa. Like the Mona Lisa, she sits upright in a dark chair and rests her hands on either a dark desk or perhaps a large dress that surrounds her. Her ungloved hand may be clasping a book or part of her sleeve. The loose brushwork is typical of Hals and shows a fleeting gesture with the casual way her finger is hooked over her wrist. Portraits of subjects with one glove on and one glove off are common in Dutch 17th-century marriage pendant portraits. Gloves symbolize the wedding vows where the husband and wife each hold one of a pair of gloves. In this case, her husband Joseph Coymans is wearing the "other glove" in his pendant portrait. In Hals' marriage pendant portraits, the husband is always situated on the left and the woman on the right, and the light always comes from the left, shining fully on the woman.