The Temple Knights
The Temple Knights are an organization answering to the Holy See of Ishgard. The organization handles national defense, protecting the public and maintaining public order, as well as other specialized duties, such as porting, sapping, etc. The Temple Knights are divided into five combat units, each headed by a Commander. The five commanders all answer to a single "Lord Commander," who serves as the de facto leader and public representative of the order.
In addition to maintaining defense and order, the Temple Knights also perform humanitarian duties for the people of Ishgard. They regularly perform training exercises with the privately-managed knights of the High Houses. Those who wish to join the Temple Knights have several avenues open to them; winning a grand tournament, recommendation from a noble or high-ranking Temple Knight for instance. However, the amount of time one may have to work to obtain knighthood is not a set length, as most who join must serve as squires for quite some time before becoming a knight proper. Once a squire becomes a knight, they can rise through the ranks through valor and perseverance, the easiest way (or most effective, perhaps) is to attain glory in battle against the Dragons, however survival rates for those who pursue this method are surprisingly low.