"... Man's gateways to the stars. Like the railways of old, they'll link our civilization together like never before - our salvation, and our damnation. Without them, our empire will surely collapse. I doubt I will live to see the first one's completion." - Directorate Consul Aurelius Immelmann
The Aurelian Gates are a huge network of interstellar FTL "highways" built by the Directorate to enable rapid Faster than Light travel across its vast dominions. They are named for the Consul who commissioned their construction, Aurelius Alexander Immelman, who, contrary to his own predictions, did live to see the completion of the initial system.
An Aurelian Gateway is a massive FTL "portal" that links to another gateway orbiting a different star and forms a massive, fixed Tannhauser-Orpheus gravitational funnel between two points. A series of "rings" that begins hundreds of kilometers ahead of the actual gateway generate an intense electromagnetic-gravitational field that accelerates vessels passing through them, before the vessel enters the mouth of the Tannhauser-Orpheus funnel and rockets through space at several hundred times the speed of light. Vessels arriving at the other end pass through the opposite set of rings, which effectively decelerate them back down to 0 velocity, before they continue their journey to one of the planets in the solar system - or to another gateway.
The Aurelian Gates, along with the "Tesla" FTL comm network, effectively link the Directorate's vast interstellar empire together. The Directorate invests vast sums of money into the construction of these monolithic structures, which are broad enough to permit the simultaenous passage of entire Navy battlefleets or shoals of massive freight cruisers. Each gateway terminus is a heavily defended military instillation, the loss of which would be a sore blow to the Directorate's power in a region. A gateway takes the better part of a century - or most of a human lifetime - to build, and becomes a lynchpin of commerce within a system. However, each gateway is slaved to a single fixed opposite gateway, so most systems that have been under Directorate control for some time have a multitude of them orbiting their stars. It is a testament to the might of Kaliban that new gateways are produced on what is essentially a weekly basis, and the Directorate's capital system alone is home to hundreds of them.