"through, by means of," 1580s (earlier in various Latin and French phrases, in the latter often par), from Latin per "through, during, by means of, on account of, as in," from PIE root *per- (1) "forward," hence "through, in front of, before, first, chief, toward, near, around, against."
c. 1200, aventure, auenture "that which happens by chance, fortune, luck," from Old French aventure (11c.) "chance, accident, occurrence, event, happening," from Latin adventura (res) "(a thing) about to happen," from fem. of adventurus, future participle of advenire "to come to, reach, arrive at." This is from ad "to" (see ad-) + venire "to come" (from a suffixed form of PIE root *gwa- "to go, come").
The meaning developed through "risk; danger" (a trial of one's chances), c. 1300, and "perilous undertaking" (late 14c.) to "novel or exciting incident, remarkable occurrence in one's life" (1560s).
Earlier it also meant "a wonder, a miracle; accounts of marvelous things" (13c.). The -d- was restored in English 15c.-16c.; in French the attempt to restore it at about the same time was rejected. Venture is a 15c. variant. German Abenteuer is a borrowing of the French word, apparently deformed whimsically by influence of Abend "evening."
"possibly," late 15c., perhappes, with adverbial genitive, from earlier perhap (mid-14c.), from per, par "by, through" (see per) + plural of hap "chance" (see happen), on model of peradventure, perchance, etc. which now have been superseded by this word. Perhappons "possibly, by chance" is recorded from late 15c.
<a href="https://www.etymonline.com/word/peradventure">Etymology of peradventure by etymonline</a>
Harper, D. (n.d.). Etymology of peradventure. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/peradventure