To Borgia

Illustrissimo Signor mio,

The new battery at Piombino stands where the cliffs drop to the sea, but the guns do not cover the northern mole as contracted. The elevation is too high; the shot passes over the mole and falls in the shallows, where the Sienese boats may still land supplies under cover of dusk. Lower the platforms by two braccia and set the embrasure mouths below the parapet crest. The embrasure itself must be widened to thirty degrees so the guns may traverse left without fouling the masonry. I have marked the cuts on the enclosed diagram with red chalk.

The stone for the lower courses is already quarried at Campiglia. Six masons can finish the lowering in eight days if the mortar sets without delay. The artillery pieces—twelve culverins of the Duke of Urbino’s gift—are to be mounted on wooden traversing platforms so they may be shifted by winch and tackle when the wind shifts from west to south-west. The platforms must be bolted to oak sleepers laid on the lowered platform; otherwise the recoil will split the masonry.

The cost remains within the estimate: 145 ducats for stone and lime, 32 for timber and hardware, 20 for the gunners’ bivouac and powder shed. The paymaster at Piombino has the funds.

If the guns are in place by the 20th of this month, the Sienese will have no safe anchorage until the spring rains.

Valete.

2026-09-12