It was established on I January 1819 by Ferdinand I King of the Two Sicilies to reward military valor and merit, and received its name to celebrate the reunification of the dominions located on both sides of the Lighthouse (Naples and Sicily) into one kingdom.
In 1829 and in 1850 the King reformed its Statutes.

The Order is divided into eight Ranks: Knights of Grand Cross with neck ribbon, cross and plate; Grand Officers, with neck ribbon, cross without St. George and plate with smaller sunburst decoration; Commanders with neck ribbon and cross; Officers, with ribbon, small tassel and cross at buttons; Knights of Law, with ribbon and cross and buttons; Knights of Mercy, with ribbon and cross at buttons; Golden medal; Silver medal.

The decoration is formed by: ruby enameled lilied cross with in the middle a white enameled round plate bearing the image of a mounted St. George running the dragon with his sword, bordered by a circle of blue enamel with the inscription "IN HOC SIGNO VINCES" and a laurel wreath. Two crossed swords edge the angles of the cross.
The decoration of the Knights of Grand Cross has a golden image of St. George hanging down from the lower arm of the cross; the Royal Crown tops it.

On the verso, a round plate with St. George in the middle, and the inscription "VIRTUTI".

The ribbon is blue and edged in yellow.

The present Grand Master is HRH Prince Charles of Bourbon Two Sicilies, Duke of Castro.



Other Orders:
- Illustrious Royal Order of San Gennaro
- Illustrious Royal Order of St. Ferdinand and Merit
- Sacred Military Constantinian Order of St. George
- Royal Order of Francis I