“In the year of Christ 1150, the ‘capannuccio’ (little hut ) raised on columns was made”, wrote the chronicler Giovanni Villani in the first half of the fourteenth century, referring to the construction of the marble lantern that crowns the Baptistery at the top. But why does he call it ‘little hut’ – words that implie a judgement of minor qualification – instead of using the more appropriate term of ‘lantern’? And why specify that it is ‘raised in columns’? Perhaps the one that was previously there did not?
Doubts that deserve an attempt at explanation.
Let’s start from when the problem arose, that is, when the dome was built with an opening at its top – an ‘eye’ – through which the rain fell into. This hole caused, in addition to obvious inconveniences, a damage of the masonry, and it is very likely that, as soon as the building was used as a church, they tried to create a protection. This protection wouldn’t be in masonry, because on the roof no traces suggest that: if it was made, it was probably in wood, like a shelter on small columns anchored to the marble but with the sides open. Some miniatures in the Chigi codex (mid-fourteenth century), as far as they can help us, indicate this.
A similar artifact would have been appropriate to call it a ‘capannuccio’; thus the term remained to denote what was on top of the roof of the Baptistery, as that of ‘scarsella’ remained to the strange rectangular apse.
If we now take a look at another miniature, that of the Codex of Biadaiolo, datable to around 1340, when the ‘capannuccio’ had already been “raised in columns” from a couple of centuries, we see that the lantern is presented without glass frames; therefore windy rain still penetrated into, threatening the stability of the large mosaics. This can be understood from a detail diligently noted by the miniaturist: at the foot of the columns we see a protection made with laths or slabs of marble placed to prevent the water of the shelf from draining into the interior. In short, the ‘capannuccio’ guaranteed a protection that was still unsatisfactory. Glass windows were necessary.
We don’t know exactly when they were posed, but the problem must have been well known to everyone for some time, also because the infiltrations made the work of the mosaicists very problematic. So why the delay?
Probably the reason was that, in order to insert the stained-glass windows, the capitals had to be chiseled, and this had to be done with great caution because the weight of the trabeation and the cusp loaded on them. Indeed, the insertions in the capitals caused many breakages, which were remedied with many similar pieces that document that there were several other capitals available, and all of them evidently could only come from the original aedicule that surrounded the ‘statue of Mars’ inside the monument.
In the title: detail of the miniature of the Codex Biadaiolo representing the episode of the Florentines giving bread to the poor people expelled from Siena by the great famine of 1328-30; note the lantern without glasses.
Below: the same miniature in its whole and a detail of the Chigi Codex of the Cronica (f. 80r) in which we see, at the ridge of the roof, what really looks like a wooden ‘capannuccio‘ (little hut), both for the shape and for the color.
In the photo on the left we see the breakages of the lantern capitals due to the forced insertion of the glass frames and the dowels with which they tried to remedy.