Crusade
late 16th century (originally as croisade ): from French croisade, an alteration (influenced by Spanish cruzado ) of earlier croisée, literally ‘the state of being marked with the cross’, based on Latin crux, cruc- ‘cross’; in the 17th century the form crusado, from Spanish cruzado, was introduced. The blending of these two forms led to the current spelling, first recorded in the early 18th century.
wiktionary
From French croisade, introduced in English (in the French spelling) by 1575. The modern spelling emerges c.1760,. Middle French croisade is introduced in the 15th century, based on Spanish cruzada (late 14th century) and Old Occitan crozada (early 13th century), both reflecting Medieval Latin cruciāta, cruxiata, the feminine singular of the adjective cruciātus used as an abstract noun.
Adjectival cruciātus originally meant "tormented; crucified", but from the 12th century was also used for "marked with a cross; making the sign of the cross" and eventually "taking the cross" in the sense of "going on a crusade".
Old Occitan crozada is used in the sense "[the Albigensian] crusade" in the Song of the Albigensian crusade, written c. 1213. From vernacular usage, Middle Latin cruciāta also comes to be used in the sense "crusade" from about 1270.
etymonline
crusade (n.)
"military expedition under the banner of the cross," 1706, a respelling or replacement of croisade (1570s), from French croisade (16c.), Spanish cruzada, both from Medieval Latin cruciata, past participle of cruciare "to mark with a cross," from Latin crux (genitive crucis) "cross" (see crux).
The modern English form is comparatively late, and even the earlier croisade is post-Middle English (French croisade replaced earlier croisée). Middle English nouns were croiserie (c. 1300), creiserie.
Especially in reference to the medieval expeditions undertaken by European Christians for recovery of the Holy Land from Muslims. Generally they are counted as seven between 1095 and 1271, but some smaller efforts (e.g. the "Children's Crusade") are omitted and the word sometimes is extended to other religiously motivated expeditions (e.g. against the Albigenses or the Prussians). Figurative sense of "vigorous campaign for a moral cause or against a public evil" is from 1786.
crusade (v.)
1732, "to engage in a crusade," from crusade (n.). The usual way to express this in Middle English seems to have been take the cross (c. 1300). Related: Crusaded; crusading.
