A TOMB containing 50 mummies dating back 2,400 years has been discovered south of Cairo. The mummies, 12 of which were of children, were discovered inside four burial chambers in the Tuna El-Gebel archaeological site, Egypt's ministry of antiquities said on Saturday. The identities of the mummies were still unknown although experts say they clearly held important and prestigious positions.They are believed to be a middle-class family who probably lived during the Ptolemaic, early Roman or Byzantine period. Mostafa Waziri, secretary-general of the Supreme Council of Antiquities, said: "We have not found names written in hieroglyphics".Some of the mummies which were buried nine-metres deep were found wrapped in linen while others were placed in stone coffins or wooden sarcophagi. Visitors, including ambassadors from several countries, gathered at the discovery site where 40 of the mummies were exhibited during the announcement ceremony.