Meaning has changed full circle for this cross; from shepherd, to ruler, and now back to shepherd
The Patriarchal Cross (French/heraldic: Patriarcale), with or without a Corpus, is a Latin Cross with an additional horizontal beam. There are several explanations for this 'extra' beam, and the most popular is that the upper beam, also seen on the Russian and Eastern Orthodox cross, represents the plaque bearing Pontius Pilate's inscription "Jesus the Nazorean, King of the Jews" (see INRI). Such a plaque is known in Latin as titulus cruces and therefore this form is sometimes called the Titulus Cross.
Another explanation is that the first beam represents the death of Jesus Christ and the second beam His resurrection.
A third view is that the first beam symbolises secular power and the second beam the ecclesiastic power of Byzantine emperors. In the 9th century, this was a political symbol used by Byzantine clerks and missionaries.
Perhaps the double-beamed cross form was first used in ancient Samaria (now Jordan) as an ideogram for rulership, since it depicted a shepherd's crook (crozier). With this ruler/shepherd image in mind, it was adopted for use as a Patriarchal Cross (also known as an Archiepiscopal Cross), which is the heraldic arms of an archbishop. 'Patriarch' is the title of a bishop who is second to the pope and has the highest rank in the hierarchy of jurisdiction. This particular cross form was the arms of the Patriarch of Jerusalem, who granted its use to the Knights Templar.
The Duke of Lorraine, Godefroy de Boullion, used this cross for his standard when he took part in the capture of Jerusalem. The cross was then passed on to his successors as heraldic arms and became known as the Cross of Lorraine.
The Lorraine and Patriarchal crosses differ slightly, in that the Cross of Lorraine has two horizontal beams of equal length. The upper beam is as close to the top as the lower beam is to the bottom. The Patriarchal Cross is similar to the Latin cross with a smaller crossbeam above the main one. On this cross, both beams are usually near the top. Occasionally, the shorter crossbeam of the Patriarchal Cross is slanted, near the bottom. This form is often confused with the Eastern Orthodox Cross, also known as the Russian Orthodox Cross.
The Cross of Lorraine originates from the Patriarchal Cross and confusingly, either name is used for either cross form.
A popular theory for the Patriarchal Cross with a lower slanted cross beam, is that it represents a footrest (suppedaneum). The slant symbolizes a balance scale showing the good thief, St. Dismas, having accepted Christ would ascend to Heaven and be on God's right hand, while the thief who mocked Jesus would descend to hell. In this interpretation, Christ and the Cross is a balance of justice. This lower slanting beam is also found on the Russian and Eastern Orthodox cross.
In ecclesiastical processions an archbishop is preceded by a his cross-bearer. This Processional Cross is silver or gilded and bears a Corpus. The cross is carried with the figure turned towards the archbishop.
In Freemasonry, the Patriarchal Cross is often angled like the St. Gilbert Cross. (A single barred cross is known as a Passion Cross and with three bars is known as a Salem Cross, signifying the ultimate rank of the wearer. See also Cross and Crown.)
The Patriarchal Cross may be referred to as a Double Cross but this might be confused with the meaning 'cheat' or 'betray'. The term Double-Beamed Cross avoids this confusion.
The origin of (the betraying) 'doublecross' is unclear. William Stevenson's book, 'A Man Called Intrepid', about the World War II spymaster of the British secret service, claims that operations were planned in room 20 of the the headquarters building. The numberplate on the door displayed the Roman numerals 'XX', which gave one mission the code word 'Doublecross'. It's a plausible story but the term was in use long before the Second World War (for example W Harrison Ainsworth's 1834 poem 'Double-cross', re-published in Musa Pedestris, Three Centuries of Canting Songs and Slang Rhymes).