The "Cavalier" dress refers to men with flowing ringlets, high leather boots, brightly colored fabrics, lace collars, and elaborate trimmings. The word "Cavalier" described the Royalist factions in the English Civil War (1642-1651), although Van Dyck painted portraits of Royalist and Parliamentarian leaders before the war. In fashionable portraiture over the next centuries, especially in England, "Cavalier" style was a popular way to be presented.

The most famous "triple portrait" is the one that Sir Anthony van Dyck painted of King Charles I of England in 1635 or 1636. The painting was supposed to be used as a model for a bust, and the three different angles of Charles' face were intended to allow for a possible three-dimensional model. The painting became widely copied in the next few centuries, as it not only showed off the subject but also exhibited the skill of the artist.

An orrery was an early form of planetarium, and it was meant to show how the planets move in the solar system.  The light projecting from the left side was meant to represent the sun.  The philosopher is demonstrating what happens during an eclipse in this image.

Image is in the public domain, accessed through Wikipedia Media Commons: https://en.wikipedia.org/wiki/File:Wright_of_Derby,_The_Orrery.jpg

Wright uses tenebrism in A Philosopher Giving a Lecture on the Orrery. Tenebrism is using very contrasting lights and darks, to the point that the the darkness dominates the image. This then emphasizes the light spots even further -- in this painting, the parts lit by candlelight are very noticeable in comparison to the rest of the image. Wright painted several "candlelight pictures," and he was influenced by Caravaggio, who also made use of tenebrism in many of his works.

Image is in the public domain, accessed through Wikipedia Media Commons: https://en.wikipedia.org/wiki/File:Wright_of_Derby,_The_Orrery.jpg

As a Rembrandt portrait, the most notable and identifiable quality of the painting is its chiaroscuro lighting, or its use of extreme light and shadow. Rembrandt was not known for visible brushstrokes or vivid colors, and neither are on display here. The textures are not especially unconventional, and in any case that fact and the use of an older subject are not immediate signifiers of Rembrandt's work.

Image is in the public domain, accessed through WikiArt: http://www.wikiart.org/en/rembrandt/old-man-with-turban

El Greco, born in Crete with the name Domenikos Theotokopolous, only arrived in Spain in 1577, when he was 36. Nonetheless, he established himself as an important painter in Renaissance Spain, with a unique style that both imbued other traditions and had iconoclastic touches. His work is largely known for its angular figures, dark color palette, and thick black outlines on many shapes.

Gilbert Stuart was one of the first well known American born artists, living through the American revolution. Stuart painted portraits of almost all the important figures in the Revolutionary War, creating the established portraits of the early leaders of the American republic. Stuart's work was clear and realistic owing a great deal to the neo-classicalism and realism popular in Europe in his time.

Anthony van Dyck was born in the Netherlands in 1599, but moved to Italy to study art in 1621 and became the official court painter in London in 1632. Van Dyck performed the normal function of a court painter by painting portraits of the royal family and associated people, but in a beautiful style. Van Dyck also made interesting compositional choices, such as his portrait of King Charles with three different profiles of the monarch in one painting.

Both of these paintings are images of a Spanish Royal Family, set some one hundred and fifty years apart. They are connected by more than location, however, as Diego Velázquez' Las Meninas (1656), shown in Figure 1, was such a famous and influential painting that Francisco de Goya intentionally modeled his 1801 painting Charles IV of Spain and His Family, shown in Figure 2, on the earlier work. Each painting shows the Royal Family of Spain in a relaxed and somewhat informal pose in a natural setting.

Figure 1: Las Meninas by Diego Velázquez (1656)

Figure 2: Charles IV of Spain and His Family Francisco de Goya (1801)

Philip IV ruled Spain and its territories and colonies when it was the largest power on the globe, during the seventeenth century. Philip IV wished to present himself as a magnificent figure, and he hired the best painter in Spain, Diego Velazquez. Velazquez's portraits of the royal family and its attendants conveyed their wealth and prestige, along with an inner psychology that made Velazquez one of the masters of Baroque painting.