Mensural notation was a complex system, and it took years of training to learn how to read and write it. However, it was the standard notation for music for centuries, and it was used to write some of the most famous music in history.
In the sixteenth century, a new system of notation called staff notation began to be used. Staff notation is similar to mensural notation, but it uses a simpler set of symbols and it is easier to read and write. Staff notation quickly became the standard notation for music, and it is still used today.