The Baroque era continues the renaissance interest for Classic Greek and Roman style and learning, but gives it a new twist. While the Renaissance had taken about a century to conquer all of Europe, the Baroque style spread within a matter of a few decades.
The Flanders/Netherlands region continued and expanded its influence on art through Rubens, Rembrandt, van Dijck, Buytewech, Hals, Vermeer and numerous others. French and Italian painters pale next to them, at least if you look for renderings of real human beings. The leadership of the region was probably due to a bourgeois merchant culture founded on the Calvinist belief that God's favour manifested itself in economic success. Those who paid for art, therefore, were not kings or princes, but non-noble people who were proud of having earned their wealth. Apparently, they were not interested in antique gods and goddesses, royal splendour or even saints, but in portraits of themselves and real-life scenes of their own kind, with an emphasis on businesslike sobriety, happy families and just a hint of devout modesty.
Emerging protestantism also caused a re-awakening of the awareness of mortality and the briefness of life. Whether the baroque enjoyment of life evoked morbid traits in art as a counter-balance or the other way round can be disputed - fact is that both manifested themselves. Death dance and memento mori are as frequent as the merry company.
While the Renaissance had been in love with realism and perspective, the Baroque painters began to employ light , or rather the contrast of light and shadow to evoke depth and mood. Rembrandt's Night Watch is considered the example of how the background is shrouded in darkness, while the foreground figures stand in the light.
As the Maniera style dies out, actual realism returns and combines with the leading merchant (i.e. non-noble) cultures to produce an as yet unknown wealth of material about the working classes. In upperclass portraits, both fabrics and body shapes can very probably be trusted to be accurately rendered.