c. 1200, bisecen "to entreat, beg urgently," from Old English besecan; see be- + seek. "In contrast to the simple vb., in which the northern seek has displaced the southern seech, in the compound beseech has become the standard form" [OED]. Cognate with Old Frisian biseka "deny, dispute," Dutch bezoeken, Old High German bisuochan. German cognate besuchen is merely "to visit." Related: Besought (OED writes that beseeched is "now regarded as incorrect"); beseeching.