Before cameras were invented, the only way of recording a famous person or event was by making a painting or sculpture of it. This category of art is known as historical art. Historical art is a picture of a famous person or important event in history.
Some people wonder why some portraits, for example, Napoleon Bonaparte, have one hand tucked into their vest, or hidden behind their back. They wonder if the pose is supposed to communicate something. Sometimes, a pose has a meaning. For example, if a statue of a person riding a horse has all four of the horse’s feet on the ground, the person died of natural causes. If one of the horse’s hooves is in the air, the person was wounded in battle. If both front feet are in the air, the person died in battle.
But hands in portraits don’t have a meaning like that. One hand is hidden because most artists had a hard time making the hands look matched. If both hands are showing, the nails, length and size have to look like mirror images of each other. Some artists had a hard time making them look like a set. The easy way out was to hide one of them.
Some paintings of George Washington showed him standing behind a desk with one arm behind his back while others showed both legs and both arms. Prices charged by painters were not based on how many people were to be painted, but by how many limbs were to be painted. Depicting both arms and legs would cost the buyer more. Hence the expression, "Okay, but it'll cost you an arm and a leg."
After learning the basic skills for drawing a face, students in middle school and high school can work on a self-portrait, or draw from a picture in a magazine.