Where did music come from, and why are we so drawn to it? Though various scholars have offered a diverse set of hypotheses, none of these existing theories can fully encapsulate the complexity of music. They generally treat music holistically, but music is not monolithic. Musical ability encompasses myriad component parts, such as pitch perception and beat synchronization. These various musical elements are processed in different parts of the brain. Thus, it is unlikely that music arose in one place, at one time, in response to one evolutionary pressure. While existing theories can explain pitch-related aspects of music, such as melody and harmony, they fail to encapsulate rhythm. I explore rhythm’s connection with motion, social function, and the brain in order to investigate how and why it may have evolved. In order to do so, I use diverse lines of evidence, such as my own ethnomusicological fieldwork, autism studies, and brain scans of monkeys. I hypothesize that the mirror neuron system, a mechanism in the brain that allows cognitive and physical synchronization, may be behind the connection between rhythm, movement, and social cognition. When eventually rhythm was joined with pitch manipulation activities, music as we know it was born.