Theoretical physicists have been made famous by such names as Albert Einstein, Isaac Newton and Stephen Hawking. These great minds have provided watershed moments in science and their ground-breaking research has enhanced our understanding of the universe in which we live.
Someone who studies theoretical physics might never see the inside of a laboratory, but their work is crucially important. They formulate mathematical models to decipher the mysteries of the universe. Their work also aims to affirm the work of experimental physicists.
A strong mathematics and calculus background is advantageous for a theoretical physicist to have, so incorporating mathematics into your major would stand you in good stead if you want to specialize in a branch of theoretical physics.