Central-Plan Church, a Ravelin, and an Overloaded Arch
Ground plan of a domed church with fortification studies and a note on where arches fail
This sheet pairs an elaborate ground plan of a centrally-planned domed church, an octagonal core ringed by round and quatrefoil chapels, with several fortification and structural sketches. Leonardo shows how to shape a ravelin so the enemy cannot use it as a shield or shelter, keeping the defensive line a-b above the attacker, and adds a corner tower and a quadrangular tower reached by ramps to mid-height. A terminal arched gateway carries the note that arches loaded to excess break along the straight line a-b.
On this page
Ground plan of a central-plan domed church
A large, carefully ruled plan sets an octagonal central space within a square and surrounds it with round and quatrefoil satellite chapels. It continues the series of centrally-planned church studies running through these folios.
Shaping a ravelin so the enemy cannot shelter (a-b)
Every ravelin should be built so the enemy cannot make a shield or shelter of it. Leonardo says to form it as shown above so that the offensive line a-b takes its position above the enemy.
Corner tower and ramped quadrangular tower
The sheet includes a corner of a fortification carrying an angular tower and a quadrangular tower reached by access ramps rising to mid-height. Both are drawn as small perspective studies without accompanying prose.
Where an overloaded arch breaks (a-b)
A terminal arched gateway is drawn with the letters a and b at its springing. The note reasons that all arches loaded to excess give way along the straight line a-b.