Christian bishops reframed this as a Christian symbol. The most commonly encountered Christogram in English-speaking countries in modern times is the Χ (or more accurately, Chi), representing the first letter of the word Christ, in such abbreviations as Xmas (for "Christmas") and Xian or Xtian (for "Christian"). Chi Rho (ΧΡ) The Alpha and Omega symbols may at times accompany the Chi-Rho monogram. Since the 17th century, (; also ) has been used as a New Latin term for the Chi Rho monogram. Because the was used as a kind of "invocation" at the beginning of documents of the Merovingian period, the term also came to be used of the "cross-signatures" in early medieval charters. in this context may refer to the Merovingian period abbreviation I. C. N. for , later (in the Carolingian period) also I. C. for , and still later (in the high medieval period) just C. for . St Cuthbert's coffin (late 7th century) has an exceptional realisation of the Christogram written in Anglo-Saxon runes, as ᛁᚻᛋ ᛉᛈᛋ, transliterated to the Latin alphabet as 'IHS XPS', with the chi rendered as the eolh rune (the old z or algiz rune) and the rho rendered as the p-rune. IHS In the Latin-speaking Christianity of medieval Western Europe (and so among Catholics and many Protestants today), the most common Christogram became "IHS" or "IHC", denoting the first three letters of the Greek name of Jesus, , iota-eta-sigma, or . The Greek letter iota is represented by 'I', and the eta by 'H', while the Greek letter sigma is either in its lunate form, represented by 'C', or its final form, represented by 'S'. Because the Latin-alphabet letters I and J were not systematically distinguished until the 17th century, "JHS" and "JHC" are equivalent to "IHS" and "IHC". "IHS" is sometimes interpreted as meaning or in Latin (or ) , ('Jesus, Saviour of men [or: of Jerusalem]' in Latin) or connected with . English-language interpretations of "IHS" have included "In His Service". Such interpretations are known as backformed acronyms. Used in Latin since the seventh century, the first use of IHS in an English document dates from the fourteenth century, in Piers Plowman. In the 15th century, Saint Bernardino of Siena popularized the use of the three letters on the background of a blazing sun to displace both popular pagan symbols and seals of political factions like the Guelphs and