The name Iacopi or Jacopi may be come from a genitif of Iācopo or Jācopo, (Giacopo) from Greek Iākobus or Iākobos = Giacomo (Jack)) which also come from the Hebrew patriarca Jacob (brother of Esaų and son of Isaac and Rebecca) through different modifications.

Jacob in Hebrew Ya'aqob (Yahaqōb), is according to Emilio de Felice, the union between YA, abbreviation of Yahweh (God) and probably QB (to protect), with the signification of“protect by God”.

For others – Garzanti Dictionary for example – it means “The one who rise himself or raising. The Hebrew term Ya'aqob it at the origine in the Greek language of two different form for the same name, also different for the accentuation..

At the beginning Iakōb, from the latin Iacōb or Iacobus (Jacob) ;
Subsenquently (tradition Greek-bizantina Iākobos, from which the latin Iacobus (Giācobo or Jācobo).. So this Christian name assere himself in Italy during the high Middle-ages in a twofold latin tradition (Iacōbus) e Greek-bizantina (Iākobos) and so they determined the modern shapes, different by accentuation and phonetics according to various adaptations. Iacōbus give therefore the contemporary GIACOBBE, while from Greek-bizantine Iākobos (Giacobo or Jācobo) we obtain instead , conserving the accent and adapting the letters “b” in “m” or in “p”, the modern form of Jācopo o Giācopo and of Jācomo or Giacomo.

The use of last names, also widely employee by roman people, was practically lost with the forfeiture of the roman empire, and turn back in vogue in the illustrious families or of noble lineage, around 1000 – 1100, while for common people the rule not written but used was the name followed by the patronyme or the nickname or native place all this was enough to distinguish a familiar group from another. It is only at the end of the 14th century beginning of the 15th century that last name are used again between common people and this is characteristic of the custom in Florence it has to be put in relation with the praxis of regular scrutinies and the extraction of candidates for public charge. The individuals the whose relationship more grip paternal ancestry was previously ascribed in the office, were admitted at the scrutinies as “benefiziati”, while instead the last arrived was voted separately. The families (lineages) established in the group of people in charge in the office had generally a last name, even if it will need some generations for maturing a real stable last name. In fact in the cadastre in 1427, only 36 % of the heads of household reported are listed with the last name, but in the registration in the archives called “delle Tratte” although 84 % of the men ascribed in the three greater councils had a last name, to for head of 64 % of the men ascribed in the register of the Arts ( (the elected people in the minor arts had less probability to have a last name in spite of the one selected in the greater one). All the individuals were in any case indicated by patronymes (sometimes with three grades of ancestry: father gran-father and great-gran-father) but some had no last name. Some people with the same last name had generally blood tie, even if distant, and they were for more scrutinized in the same quarter and “gonfalone”(although that some people o familiar branch changed his just quarter and “the gonfalone”). The last names derived soon from the patronymes (Alberti da Alberto, Capponi da Cappone, Ridolfi da Ridolfo Iacopi da Iacopo, although this procedure was not automatic. The Capponi, for example, which accessed to the “Priorato” the first time in 1287, adopted a fixed last name only in the middle of the 14Th century. However in this particular case the genealogical relationship between the members of the family was very clear, although origanl documents did not identificate any one with the patroynime or the last name “Del Cappone”.

The last names sometimes are derived form the native places. Good examples are Da Ghiacceto i Diacceto, i Da Panzano, i Da Terrazano ed i Da Uzzano. Finally some times the families hesitated between two last names: This the case very famous of a branch of the Tornaquinci Family (magnates and so excluded the the offices), wich recycle themselves in “popular” in order to obtain the right to be elected and change as we will see, the name in “Tornabuoni”.