This is a great question. The Baroque period is known for an ornate and exuberant style. Some have described it as dramatic. It started around the 1600's from Italy and spread to the rest of Europe. Another important element is that this movement started right after the Protestant Reformation and coincided with the Counter-Reformation of the Catholic church. This was not by chance. According to scholars this was a very direct attempt of the Catholic church to reassert itself in the face of growing Protestantism. The excessive qualities of baroque art, according to some was to mask the insecurities of the church.
Another element of baroque art was the change of subjects. In other words, the object of art was now more common, like street people or even objects. Caravaggio would be an example of this. We can also see this in the works of Rembrandt and Vermeer.