c. 1200, "make the sign of a cross as an act of devotion," from cross (n.) and in part from French croiser. Sense of "to go across, pass from side to side of, pass over" is from c. 1400; that of "to cancel by drawing a line over or crossed lines over" is from mid-15c.
From late 14c. as "lie across; intersect;" also "place (two things) crosswise of each other; lay one thing across another." From early 15c. as "mark a cross on." Meaning "thwart, obstruct, hinder, oppose" is from 1550s. Meaning "to draw or run a line athwart or across" is from 1703. Also in Middle English in now-archaic sense "crucify" (mid-14c.), hence, figuratively, crossed "carrying a cross of affliction or penance."
Sense of "cause to interbreed" is from 1754. In telegraphy, electricity, etc., in reference to accidental contact of two wires on different circuits or different parts of a circuit that allows part of the current to flow from one to the other, from 1884. Meaning "to cheat" is by 1823.
Cross my heart as a vow is from 1898. To cross over as euphemistic for "to die" is from 1930. To cross (someone's) path "thwart, obstruct, oppose" is from 1818. Of ideas, etc., to cross (someone's) mind "enter into" (of an idea, etc.) is from 1768; the notion is of something entering the mind as if passing athwart it.