Certaldo is one of the castles of the Valdelsa that preserves the aspect that it had taken on by the end of the Late Middle Ages. It was in this form that Leonardo depicted it in one of his most famous maps, the great bird's-eye view of the Windsor Castle Collection RL 12278. In this large map Leonardo represented the entire system of left tributaries of the middle Valdarno, with the mapping of castles having superior strategic value during that time frame. Among these is the towered profile of the castle of Certaldo. Its origins date back at least to the second half of the 12th century, when the network of roads of the Via Francigena had moved to the right side of the Elsa, by contrast with the older route that, as is known, passed by San Gimignano and the parish church of Chianni, on the hills to the left of the Elsa.
In the church of Saints Jacopo and Filippo, on the left wall, the funeral monument is located that was created to honor Giovanni Boccaccio, who is buried in the cemetery of that church. The elements that make up the cenotaph, a marble portrait of the poet, a commemorative epigraph with an epitaph, and the family coat of arms, are all the work of the same hand, commissioned of Florentine sculptor Giovanfrancesco Rustici in 1503. Indeed, we even know that it was executed during the second half of the year, since it is certain that the work was ordered by the vicar of Certaldo, the Florentine Lattanzio Tedaldi, who took office in the second half of 1503. The circumstances that saw the creation of Boccaccio's cenotaph link not only artist and client—the Rustici and the vicar Tedaldi— but also the figure of Leonardo. Two years earlier, at the beginning of the 1500s, Leonardo was in Florence after a very long absence, a period of time spent above all at the court of the Duke of Milan. Back again in the city of Florence, Leonardo arranged his studio at the monastery of the Serviti della Santissima Annunziata. At that time, Giovanfrancesco Rustici was also renting a shop in that area, on Via dei Servi. And the same Lattanzio Tedaldi, who at the beginning of the 1500s was still in Florence, lived in the same area. Lattanzio Tedaldi belonged to one of the families of the city’s highest class. A character who was certainly up-to-date, and present within the philosophical and literary debate of the time, he is often remembered among intellectuals close to Ficino and the poet Filippo Buonaccorsi. Leonardo must have known Lattanzio Tedaldi if he wrote his name three times in three different memo lists, penned while he was still at the Santissima Annunziata: Codex Atlanticus, f. 331r; Codex Arundel, f. 191r; and RL 12675v. The last folio bearing the name of Lattanzio Tedaldi is the verso of one of the drawings of the hydrographic system of the river Streda, near Vinci, where Leonardo had planned to create an artificial reservoir in the place today called Serravalle. Also in one of the memo lists, that of the Codex Arundel, there is another reference to the territory of Vinci: when Leonardo pens the note la valuta del Botro "the currency of the Botro", probably making reference to the estate owned by his father ser Piero, which was in the community of Santa Croce, again, in the same area of the project by Leonardo depicted on the recto of folio RL 12675, where the name Lattanzi is found. Thus at the turn of the year 1501, the three, the future vicar of Cerreto, Lattanzio Tedaldi, the young sculptor, Rustici, and Leonardo frequented the same streets of the neighborhood surrounding the Santissima Annunziata, an area that would soon become central to the cultural elite of the city. The da Vinci and Rustici families had known each other for some time, and had the hopes that the two artist sons would spend time together. The youngest, Giovanfrancesco, trained in Verrocchio’s workshops, and Benedetto da Maiano, could thus have availed themselves of Leonardo's school and experience, already renowned for the unfortunate but impressive equestrian statue projected for the Sforza monument that was never completed. From the new shop in Via dei Servi the young sculptor had begun to weave a dense network of relationships that went beyond the environment of art, expanding to notable personages, writers, and humanists.
It is in this context that his first important public commission is inserted, the one offered him by the new vicar of Certaldo, Lattanzio Tedaldi, in the second half of 1503. This commission was decisive for the career of Gianfrancesco Rustici, which would reach its climax just a few years after the work of Certaldo, with its masterpiece, The Preaching of the Baptist. The sculptural group was commissioned in 1506 and cast at the end of 1509, to finally be raised to above the north door of the Baptistery in 1511. As Vasari recounts, the young sculptor did not want "others around except for Leonardo da Vinci" for the precious help the master could give him, especially at the time of the casting, which was carried out in December 1509. The two actually were very close during the previous year, in 1508, when Leonardo was back in Florence and lived where Giovanfrancesco Rustici's studio was. The two were already very close, but the solid friendship that united them blossomed just at the time of the commission of the Certaldo funeral monument in honor of Giovanni Boccaccio.