San Niccolò weir

Pescaia "della Giustizia" (Pescaia di San Niccolò)

In the Codex Leicester (f. 13A-13r) , Leonardo takes notes «on the Giustizia weir».
The"Giustizia" weir was located on the right bank, in the place later known as the Zecca Vecchia (old mint). From this bank of the Arno, the weir crossed the river as far as the bank in front of today's Piazza Poggi with the San Niccolò gate.

"Mulina di San Niccolò"

Around 1507 Leonardo noted in the Codex Atlanticus (f. 571a-r) «From the outflow coming from the mills in the Arno through the sluice-gate at the Rubaconte bridge»: he was referring to the mills of San Niccolò, situated on the left bank of the river.
In the Codex Arundel (f. 273v) he observes that, on the opposite bank: «the Casacce wall straightens out at the San Nicolò gate».
In the Codex Leicester (f. 7A-30v) he describes a sequence of cascades in referring to these same mills: «Against the mills of Sancto Nicolò that want no obstacle of any kind in their millcourse […]».
These were imposing fortified mills, appearing frequently in the historic iconography of Florence.

"Isola dei Cocomeri"

Leonardo notes on folio 13A-13r of the Codex Leicester: «there is a shoal, at the place where the Isola dei Cocomeri ends in the middle of the Arno».
This observation is found along with others regarding the Rubaconte bridge, the Giustizia weir, Palazzo Bisticci and Palazzo Canigiani (in Via de' Bardi). This suggests that there was an island in the Arno in the section upstream of "Ponte Rubaconte" (that is, Ponte alle Grazie) and perhaps also of the Giustizia weir, where the more frequently mentioned "Isola d'Arno" was located: the place where Pazzino Pazzi, for instance, went hunting with his falcon and was killed in 1312.

"Spedale del Ceppo"

On folio 16B-16v of the Codex Leicester, Leonardo notes observations made in the Arno «on the Rubaconte bridge, at the Torricella» and «under the Ceppo hospital».
This was the Hospital of S. Filippo and Iacopo del Ceppo, or of the Torricella, on the right bank of the Arno, until 1530 adjacent to the Companies of S. Niccolò and S. Girolamo del Ceppo. This building was located in Corso de' Tintori, near Palazzo Doni; it was here that Raphael painted the portraits of Angelo Doni and Maddalena Strozzi, probably influenced by Leonardo's Dama al balcone.

"Ponte Rubaconte" (Ponte alle Grazie)

The bridge was built in 1237 and took the name of the Milanese Podesta of Florence. It was the only other bridge, along with Ponte Vecchio, to withstand the flood of the Arno in 1833.
Crossing the river at its widest point, it had 9 arcades for a length of around 215 meters (2 arcades were closed in 1347) to make space for Piazza de' Mozzi (mentioned by Leonardo on f. 190v of the Codex Arundel); a third was closed in the 19th century to build the street along the Arno on the left bank.
Leonardo describes it, in the Codex Arundel (f. 273v), «[long] 290 and wide 12 and 2 of sides and 16 of piles»; and mentions it in the Codex Leicester, on f. 13A-13r and on f. 16B-16v («On the Rubaconte bridge, at the Torricella»). In the Codex Atlanticus (f. 571a-r) he mentions «the sluice-gate at the Rubaconte bridge».
In the mid-fifteenth century it was named "alle Grazie" for the Oratory of Santa Maria delle Grazie, built on the pillars of the bridge along with the cells of the cloistered nuns (Le Murate, which remained there until 1424) and the shops built on the bridge starting from 1292.
Ponte alle Grazie joined the houses of the Alberti family (on the right bank, today Via de' Benci) with the houses of the Mozzi family (on the left bank, still today Piazza de' Mozzi), rebuilt after 1260 in the fortified palace in line with Via San Niccolò.
The present bridge was rebuilt after having been destroyed in 1944.

Ponte Vecchio

This is the most ancient and historic of the Florentine bridges, although it was destroyed by the flood of 1333 and rebuilt in 1345 by Taddeo Gaddi, who reduced the number of arcades from five to three. The shops were added in successive stages (38 in 1427) and lastly the Vasari Corridor.
In the Codex Arundel (f. 273v) Leonardo describes it thusly: «Bridge long 152 braccia and wide [?]».

Ponte Santa Trinita

Leonardo describes this bridge in the Codex Arundel (f. 273v): «188 Wide 15 braccia and 2 of sides and 28 pillars for the sides, and the pillars are 2». Indicating the distance between the various bridges, he specifies for instance that between Ponte Santa Trinita and Ponte alla Carraia there are 410 braccia.
The bridge was rebuilt in 1567 by Bartolomeo Ammannati and the director of works, Alfonso Parigi the Elder, specifies its dimensions: width - without the sides - 17 braccia (instead of the 15 measured by Leonardo), length 168 braccia (instead of Leonardo's 188).
It joins Via Tornabuoni (Piazza Santa Trinita) to Via Maggio (Piazza de' Frescobaldi).

Ponte alla Carraia

In the Codex Arundel (f. 272v), between a list of expenses and studies on the Arno, Leonardo notes: «Hits the "muro de' compari" [the companions' wall] at the II pile of the Carraia: IV south-east…». And on folio 273v of the same codex he describes it as follows: «[long braccia] 230, wide braccia 12 and 2 of sides and 14 of piles and has 4 pillars».
Built of wood on stone pylons as the "Ponte Nuovo", or new bridge, in 1218-1220, it collapsed in 1304 under the weight of the crowd that had gathered on it to watch a representation of the Inferno for the festival of Calendimaggio; it was swept away by the flood of 1333; and was rebuilt between 1334 and 1337 (perhaps to the design of Giotto).
Destroyed in 1944 and rebuilt in the postwar period, it joins Via del Moro and Via de' Fossi (from today's Piazza Goldoni) and Via dei Serragli (with today's Piazza Nazario Sauro).

"Muro de’ Compari" (Lungarno Vespucci)

On folio 273v of the Codex Arundel, Leonardo indicates «Borgo Ognissanti 850 [braccia] » as the distance between Ponte alla Carraia and today's Santa Rosa Weir (formerly Ognissanti Weir), that is, the «muro dei compari» (companions' wall), between «the pile of Carraia" and the «pescaia de' compari» (that is, the "Ognissanti weir", as Leonardo indicates it on folio RL 12678). It was also called the "Consorti wall" in relation to the Consorteria delle Mulina d'Ognissanti (the Ognissanti mills association).

"Pescaia d’Ognissanti" (di Santa Rosa)

Leonardo mentions the Ognissanti weir in RL 12678 and it is the same «pescaia de' compari» mentioned in the Codex Arundel (f. 272v). The weir, which is clearly visible on the "Map of the Catena" from 1472, created a river port. On the left bank was the Pignone wharf near Porta San Frediano, on the right bank another landing place and the Porticciola del Prato.

"Muro dell’Uccello" (Lungarno Soderini)

In the Codex Arundel (f. 272v), Leonardo mentions «the wall of the bird at ¾ to the south-east»: this is the bank on the left side of the river, still in the section between the Carraia bridge and the Santa Rosa weir. On folio 273v, he specifies its size as only 230 braccia. In this area there was an ancient drying shop, "dell'uccel grifagno" (of the predatory bird), belonging to the Wool Merchants' Guild.

Texts by
Alessandro Vezzosi, in collaboration with Agnese Sabato / English translation by Catherine Frost