The '''Labarum''' (Greek: λάβαρον / láboron) was a Christian imperial standard incorporating the sacred '''"[[w:Chi Rho|Chi-Rho]]"''' [[w:Christogram|Christogram]], which was one of the earliest forms of christogram used by Christians and , becoming one of the most familiar and widely used emblems in Chrisitan tradition. It was adopted adapted by emperor Saint [[Constantine the Great]] after receiving his celestial vision and dream, on the eve of his victory at the [[w:Battle of the Milvian Bridge|Milvian Bridge]] in 313 AD.

The Labarum of [[Constantine the Great|Constantine]] was a [[w:Vexillum|vexillum]]<ref group="note">The [[w:Vexillum|vexillum]] (plural vexilla) was a military standard (flag, banner) used in the Classical Era of the Roman Empire. On the vexillum the cloth was draped from a horizontal crossbar suspended from the staff; this is unlike most modern flags in which the 'hoist' of the cloth is attached directly to the vertical staff. The bearer of a vexillum was known as a ''vexillarius''. The vexillum was a treasured symbol of the military unit that it represented and it was closely defended in combat.</ref> that displayed the "[[w:Chi Rho|Chi-Rho]]" [[w:Christogram|Christogram]], formed from the first two Greek letters of the word "[[Jesus Christ|Christ]]" (Greek: '''ΧΡ'''ΙΣΤΟΣ, or '''Χρ'''ιστός) — [[w:Chi (letter)|Chi]] (χ) and [[w:Rho (letter)|Rho]] (ρ). Fashioned after legionary standards, it substituted the from form of a [[cross]] for the old pagan symbols, and was surmounted by a jewelled wreath of gold containing the monogram of Christ, intersecting '''Chi''' (χ) and '''Rho''' (ρ), on which ; upon this hung a [[w:Tyrian purple|rich purple ]] banner ,<ref group="note">Purple dye at this time was a rarity derived from a shellfish of the genus ''[[w:Murex|Murex]].'' [[w:Tyrian purple|Tyrian purple]] ((Greek, πορφύρα, porphyra, Latin: purpura), also known as royal purple, imperial purple) was prized by the Romans, who used it to colour ceremonial robes.</ref> beset with gold trim and profuse embroidery, inscribed with . The inscription ''' ''"Εν Τουτω Νικα"'' (''in hoc signo vincesIn Hoc Signo Vinces'') — "In this sign, conquer" ''' was in all probability inscribed upon the actual standard, although [[Eusebius of Caesarea|Eusebius]] mentions that royal portraits of Constantine and his children were integrated.<ref group="note" >These portraits could have been embroidered, or set as [[w:Phalera (military decoration)|medallions/roundels]] on the staff. Later, the name ''Labarum' ' was given to variants of the original standard. An idea of some of the deviations in form of the standards furnished to different divisions of the army may be obtained from several coins of Constantine's reign that are still preserved. On one coin, for instance, the portraits of the emperor and his sons are represented on the actual banner (instead of as [[w:Phalera (military decoration)|medallions/roundels]] on the staff); on a second, the banner is inscribed with the Chi-Rho monogram, and surmounted by the equal-armed [[cross]] while the medallions/roundels of the royal portraits, are on the shaft below the banner. ("[http://oce.catholic.com/index.php?title=Labarum Labarum]."'' '''Original Catholic Encyclopedia).'''</ref> St. [[Ambrose of Milan]] later wrote that the Labarum was [[Consecration of a church|consecrated]] by the Name of [[Jesus Christ|Christ]].<ref>[[Ambrose of Milan]]. ''"Letter XL."'' '''St. Ambrose Selected Letters'''.</ref>

[[Image:Vexilloid of the Roman Empire.jpg|right|thumb|Modern reconstruction of a Roman [[w:Vexillum|vexillum]], emblazoned with [[w:SPQR|S·P·Q·R]] and the [[w:Aquila (Roman)|Roman Eagle]]. Emperor [[Constantine the Great|Constantine]] replaced modified the original banner, replacing the eagle with the ''Chi-Rho'' Christogram, and the motto ''"en touto nika"'' (''in hoc signo vinces - IHSV'').]]The ''Labarum'' was originally a Roman military ensign, which is described to have been a more distinguished form of the [[w:Vexillum|Vexillum]], or cavalry standard. The [[w:Vexilloid|vexilloid]] of the Roman Empire was a red banner with the letters [[w:SPQR|SPQR]] in Gold surrounded by a gold wreath, hung on a military standard topped by the [[w:Aquila (Roman)|Roman eagle]] (or an image of the goddess [[w:Victoria (mythology)|Victoria]]) made of silver or bronze.

[[w:Lactantius|Lactantius]] states<ref>Lactantius, ''[http://orderofcenturions.org/documents/lactantius.html On the Deaths of the Persecutors],'' chapter 44.5.</ref> that, in the night before the battle, Constantine was commanded in a dream to "delineate the heavenly sign on the shields of his soldiers". He obeyed and marked the shields with a sign "denoting Christ". Lactantius describes that sign as a "staurogram", or a Latin cross with its upper end rounded in a P-like fashion (i.e. a ''"[[w:Tau|Tau]]-[[w:Rho (letter)|Rho]]"'' Christogram).<ref group="note">Dr. Larry Hurtado has stated that contrary to some widely influential assumptions, this ''"[[w:Tau|Tau]]-[[w:Rho (letter)|Rho]]"'' staurogram appears to be the earliest of the Christograms, and not the more familiar ''"[[w:Chi Rho|Chi-Rho]]"''. He writes that the earliest extant Christian use of the ''"Tau-Rho"'' is not as a freestanding symbol and general reference to ChirstChrist, but in manuscripts dated as early as around 175-225 AD, where it functions as part of the abbreviation of the Greek words for "cross" (σταυρός) and "crucify" (σταυρόω), written (abbreviated) as ''[[w:Nomina sacra|nomina sacra]]''. (Hurtado, L.W. ''[http://books.google.ca/books?id=w5FpP9ZxqlYC&source=gbs_navlinks_s The Earliest Christian Artifacts: Manuscripts and Christian Origins].'' Cambridge, 2006. p.136.)</ref>

Fifty soldiers of the imperial guard''(ὑπασπισταἰ)'', distinguished for bravery and piety, were entrusted with the care and defense of the new sacred standard , which was to be borne by them singly by turns (''Vita Constant.'', II:8). Standards, similar to the original labarum in its essential features were supplied to all the legions, and the monogram was also engraved on the soldiers' shields.<ref>Hassett, Maurice. ''"[http://www.newadvent.org/cathen/08717c.htm Labarum (Chi-Rho)]."'' '''The Catholic Encyclopedia.''' (New Advent). Vol. 8. New York: Robert Appleton Company, 1910.</ref>

The sacred symbols were naturally removed from the standards by [[Julian the Apostate]], but were restored by Jovian and his successors, and continued to be borne by later Byzantine emperors.<ref>[[w:William Smith (lexicographer)|Smith, Sir William]] and Samuel Cheetham (eds.). ''"[http://books.google.ca/books?id=omMaAAAAYAAJ&source=gbs_navlinks_s Labarum]."'' '''A dictionary of Christian antiquities: Being a continuation of the ʻDictionary of the Bible', Volume 2.''' J. B. Burr, 1880. p.910.</ref> The Labarum marked with the monogram of [[Christ]] is seen on the coins of [[Constantine the Great]], and also of Constans, of JovianusJovian, and of ValentinianusValentinian, to the end of the [http://www.forumancientcoins.com/numiswiki/view.asp?key=Imperial%20Series imperial series].<ref>''[http://www.forumancientcoins.com/numiswiki/view.asp?key=labarum Labarum].'' '''Numiswiki: The Collaborative Numismatics Project.'''</ref>

Later usage has sometimes regarded the terms "labarum" and "Chi[[Image:Theotokos-Rho" as synonyms (iStandard.eJPG|thumb|right|Modern Orthodox Labarum. Embroidered icon of the labarum bearing the chi-rho symbol). Ancient sources however draw an unambiguous distinction between the two, since the "Chi-Rho" [[w:Christogram|ChristogramTheotokos]] with [[Christ]] and the "Labarum" were not originally synonyms. As noted above, the labarum was originally a type of ; [[w:VexillumDeesis|vexillumDeësis]], a military standard used icon in the Classical Era of the Roman Empire, with a flag hanging from a horizontal crossbarlower panels; the Chi-Rho Christogram was only added to the flag surmounted by the Emperor [[Constantine the Great|Constantine Icross]].]] in Later usage came to regard the terms "Labarum" and "Chi-Rho" as synonymous, although ancient sources draw an unambiguous distinction between the late Roman periodtwo due to their separate origins.

In addition, Christians' use of the sacred "Chi-Rho" Christogram was not always used is connection with the imperial labarum, but its use by Christians naturally evolved expanded into a variety of other areas and formats, including as well. This included on coins and medallions (minted during Constantine's reign and by subsequent rulers), becoming part of the official imperial insignia after Constantine, ); on Christian sarcophagi and frescoes from about 350 AD, ; and eventually appearing on public buildings and churches as well.

A later Byzantine manuscript indicates that a jewelled labarum Labarum standard believed to have been that of [[Constantine the Great|Constantinethe Great]] was preserved for centuries, as an object of great veneration, in the imperial treasury at [[Church of Constantinople|Constantinople]].<ref>Lieu and Montserrat p. 118. From a Byzantine life of Constantine (BHG 364) written in the mid to late ninth century.</ref> The labarumLabarum, with minor variations in its form, was widely used by the Christian Roman emperors who followed Constantine I. A miniature version of the Labarum became part of the imperial regalia of [[Byzantine Empire|Byzantine]] rulers, who were often depicted carrying it in their right hands.

A miniature version of the labarum became part of the imperial regalia of [[Byzantine Empire|Byzantine]] rulers, who were often depicted carrying it in their right hands. In the Middle Ages the pastoral staff of a bishop often had attached to it a small purple scarf known as the vexillum, supposedly derived from the labarumLabarum.<ref>''"Labarum."'' '''Encyclopædia Britannica.''' Encyclopædia Britannica 2009 Ultimate Reference Suite. Chicago: Encyclopædia Britannica, 2009.</ref> The Chi-Rho monogram is also found on Eucharistic vessels and lamps.<ref>-----. ''"Chi Rho (XP)."'' In: Steffler, Alva William. '''Symbols of the Christian Faith.''' Wm. B. Eerdmans Publishing Company, 2002. p.66.</ref>

Today, the term "labarumLabarum" is generally used for any ecclesiastical banner, such as those carried in religious processions.<ref group="note">Some Protestant Christians (especially Restorationists) reject the use of Labarum Christogram due to its supposed pagan origins and lack of use by the earliest Christians. Supporters point out that use of the Labarum was already in widespread use by Christians by the mid-fourth century, mostly on sarcophagi.</ref>

Image:San Vitale in RavennaHinton St Mary Mosaic.jpg|The [[w:Hinton St Mary Mosaic|Hinton St Mary Mosaic]], mid 4th-c., featuring a portrait bust of [[Jesus Christ]] with the ''Chi-Rho'' symbol as its central motif. Image:JustinianStVitale.jpg|Mosaic of Emperor [[Justinian]] with his retinue, with the Labarum displayed on a soldier's shield. (Ravenna, before 547 AD).

Image:KellsFol034rChiRhoMonogram.jpg|The [[w:Book of Kells|Book of Kells]], Folio 34r, containing the Chi-Rho Monogram (ca. 800 AD).

Image:Bishop-Germanos-1821.jpg|Bp. [[Germanos of Patra|Germanos of Old Patras]] blessing the Greek banner (Labaro / Λάβαρο) at [[w:Agia Lavra|Agia Lavra]] monastery, 25 March 13, 1821. Image:Wurzach St Verena Kirchenfahnen Taufstein.jpg|Modern ecclesiatical Labara from the Roman Catholic [[w:Rot an der Rot Abbey|Abbey Church of St. Verena]], Rot an der Rot, Baden-Württemberg, Germany.