IHS
A Christogram (Latin Monogramma Christi) is a monogram or combination of letters that forms an abbreviation for the name of Jesus Christ, traditionally used as a Christian symbol. One of the oldest Christograms is the Chi-Rho. It consists of the superimposed Greek letters chi (Χ) and rho (Ρ), which are the first two letters of Greek χριστός "Christ". It was displayed on the labarum military standard used by Constantine I in AD 312. The IX monogram (Christliche Symbolik (Menzel) I 193 4.jpg) is a similar form, using the initials of the name Ἰησοῦς (ὁ) Χριστός "Jesus (the) Christ", as is the ΙΗ monogram (IH Monogram with iota and eta superimposed.jpg), using the first two letters of the name Ἰησοῦς "Jesus".

There were a considerable number of variants of "Christograms" or monograms of Christ in use during the medieval period, with the boundary between specific monograms and mere scribal abbreviations somewhat fluid. The name Iesus has the abbreviations IHS (also written JHS, IHC, or ΙΗΣ), the name Christus has XP (and inflectional variants such as XPO, XPS, XPI, XPO, XPM). In Eastern Christian tradition, the monogram ΙϹΧϹ (with titlo indicating scribal abbreviation) is used for in both Greek and Cyrillic tradition.