The Teresi family is original of Palermo, Sicily.
Jacobo was born in Salonica in 1886. He is the son of Domenico and Maria Nissan Hessegigan. In the beginning Domenico is on-board machinist and travels intensively then settles down and works as chief machinist in the Italian navigation Company Florio et Rubattino which runs a steamline between Salonica and the Italian ports of Leghorn and Genoa). His brother Simon Teresi is a doctor at the Italian hospital in Salonica.
Jacobo will work for the Chemins de Fer Orientaux, then Chemins de Fer Helleniques more precisely in the construction of the railway Thessaloniki-Monastir, then the line Thessaloniki-Alexandroupolis-Constantinople.
He gets married in Salonica in 1912 with Adélaïde "Ida" Rossi, the fourth of the seven daughters of Paolo Rossi (see topic). They will give birth to two children, Ada and Aldo.
The very frequent professional trips of Jacobo will cause the staying of the two children at the Dobrowolski pension, Zanna Street in Salonica (today Vassilissis Olgas Street), not far from the Grands Moulins d'Orient of the Allatini family. Still to be found the link between this pension and the family of Conrad Dobrowolski (see topic).