Har ila yau, sun bar abubuwa masu yawa, waɗanda aka gano a cikin ƙididdigar ƙididdiga ta hanyar masu binciken ilimin kimiyya a cikin'yan kwanakin nan.
Tabbas, mafi rikitarwa na jumla shine "Sun kuma bar kayan tarihi da yawa, waɗanda masana kimiyyar kayan tarihi suka gano su da yawa a cikin 'yan kwanakin nan. Su ne kawai mutanen da suka kafa sabbin birane a yammacin Turai bayan faduwar Daular Roman amma kafin tashin Carolingians. "