Г313
ГОРА РОДИЛА МЫШЬ (sent
fixed WO great efforts yielded insignificant results, or a person promised much but delivered little
the mountain brought forth a mouse.
The source of the Russian idiom is most likely Horace (65-8 B.C., Ars poetica: 139, "Parturient montes, nascetur ridiculus mus" "Mountains will heave in childbirth, and a silly little mouse will be born") or Aesop through Phaedrus.