The most common orders of knighthood in the Imperium are the Order of the Emperor's Guard, established in 52 and originally limited to the Emperor's personal retainers but now of wide and diverse membership, and the Order of Starship and Crown, established in 17. More exclusive orders have also been established: the Order of Hlyuea (established to honor loyal Aslan citizens), the Order of Gvadakoung (established to honor loyal Vargr citizens), and the Order of the Arrow, (established to recognize interstellar explorers). The domains each have orders named for them: The Order of Antares, the Order of Vland, the Order of Sylea, the Order of Sol, the Order of the Gateway, and the Order of Deneb. Of these, the Order of Sylea is administered by the Emperor himself (as de facto Archduke of Sylea); the Order of Deneb has never been used, as no Archduke of Deneb has ever been named.