Sangallo Serif is a typeface designed between 2021 and 2022 for Biblioteca Comunale degli Intronati, one of the oldest cultural institutions in the city of Siena. The project takes inspiration from the letterforms found in the 'Taccuino Senese' by Giuliano da Sangallo, a sculptor, architect, and military engineer from the Italian Renaissance. Within the notebook, preserved at the Biblioteca Comunale degli Intronati, architectural drawings and plans alternate with sketches of a serif typeface characterized by upward-curving serifs. The alphabet designed by Giuliano da Sangallo can be associated to the Roman Lapidary typefaces with capitals designed on a square base. His curvilinear serifs has been integrated into one of the 9 stylistic sets only for uppercases. Others stylistic features standardize wider capitals to narrower ones and formal variations of the same letters. Sangallo Serif shows evident contrasts making it stand out in display uses, while maintaining a good readability even at medium-small text sizes. The typeface is composed of four weights, with matching italics.