Irishman Patrick S. Gilmore started the concept of a bandleader. A marching band is typically led by one or more drum majors, also called field commanders, who are usually responsible for conducting the band (sometimes using a large baton or mace, though such tools are used rarely in modern marching bands for conducting) and are commonly referred to as the leader of the band. When there is more than one drum major, one may be the head drum major, who often stands upon an elevated podium located on the 50-yard line while conducting, whereas the other(s) often conduct from convenient angles (should the marching block not be facing forward) and function as an apprentice of sorts. The number of members in the band often determines how many drum majors are needed, based on the complexity of the show (in which case, in a three-person scenario, one stands on the 50-yard line while another stands on the 30-yard line and the third stands on the other 30-yard line), and occasionally, additional individuals may be asked to perform brief conducting duties if beneficial in a particularly tricky part of the show (more often, such people are those on the sidelines or in the pit). The modern-day concept of the drum major has been exponentially expanded upon by George N. Parks, often known as the "Dynamic Drum Major," through his Drum Major Academy. Bands may also be led by a more traditional conductor, especially during field shows, where a stationary conductor on a ladder or platform may be visible throughout the performance. Aural commands—such as vocal orders, clapping, or a whistle—may be used to issue commands as well. In show bands, particularly in HBCU and Big Ten bands, drum majors often have a visual on-field role with a baton or mace, with the job of conducting assigned to the band director(s). In these cases, the number of drum majors is often based on tradition, rather than being in proportion with the number of musicians. For example, the Florida A&M Marching 100 fields one drum major for each president in the university's history. Other leaders within the band may include field lieutenants and captains of sections such as brass, drumline, and woodwinds, and members that lead a section, squad, row, etc.