embattle

From Middle English enbatelen, embatailen, from Old French embataillier (“to array for battle”), from em- (Latin in) + bataille (“battle”).

From Middle English enbatelen, enbatailen, from Old French *embastiller ("to fortify"; > Middle Latin imbataliare, imbattajare), from en- + + bastiller (“to build, fortify, embattle”). More at baste.