Although the gateway arch was initially intended to have been based on Serlio’s Libro Estraordinario, as it has unfolded it has become the Mannerist Gateway. The inside façade is based on Michelangelo’s Porta Pia, the outside one on Giulio Romano’s Palazzo del Te. One can suppose that Giulio created the external facade of the Porta Pia in the 1520s and it was destroyed during the Risorgimento (or earlier), and Michelangelo did the interior in the 1560s. Giulio, of course, anticipated the realignment of the Via Nomentana made by Pius IV …
This facade is currently under construction.
I always intended to make the exterior façade more aggressive and defensive than the interior façade, and so I toyed around for a while with massive rounded rustication. The ideal of an imminently falling keystone, like David Roberts’ view of a gateway at Baalbek was attractive (Fig. 1). I have also long had in mind the architecture parlante of Delafosse’s design for an imaginary prison, but this was a bit har to develop in this context. This lead me to various ruin fabriques at Schönbrunn (Fig. 2) and Eremitage (Figs 3, 4), the latter being more promising. This, however, really does read as a collapsing ruin, and is a bit too realistic. At one point I toyed with the idea of a broken lintel, tilting downwards in the middle, with big rusticated blocks above. In the end I decided this was a bit crass, a bit like something a contemporary starchitect like Gehry would do, like leaning or twisted office towers.
Eventually I settled on one of the interior courtyard facades of Palazzo del Te (Fig. 5). This is the complicated façade with the entrance. The pediment on brackets with the big rough keystone may look a little simplistic and linear but I seemed to work in the new context. The Doric entablature has the famous slipped triglyphs, one of the signature motifs of Giulio Romano’s Mannerism (Fig. 6). As Giulio uses it, it is more ornamental than threatening. That is, it does not convey a sense that the building is collapsing, but rather draws attention to the cleverness of the architect and to the way an entablature is constructed. As adapted, it is even more a sign rather than being expressive, in this case what it signifies, to the architecturally literature, is its source in Giulio Romano. Not being very expressive in itself, it is probably invisible to the profane observer.
The pediment and keystone, by contrast, have emerged as quite heavy and gutsy, and should have some expressive power (Fig. 7). Adapting this for once proved quite easy and pleasurable. I wanted to retain Giulio’s play of contrasts between rough textured blocks and smooth one. When I make the rough ones actually rough remains to be seen, but it might be worth pursuing, perhaps by mixing something gritty into the paint. Mostly I am relying on the distinction between timber 45 mm thick with rounded edges, and timber 35 mm thick with square edges. The design requires that these slabs be overlapped, and I am determined to properly master the router so I can do better lapping and tongue and groove joints. I have also realised that a planer-thicknesser might be useful, but this is an additional expense and I have nowhere to put these tools which have to be kept outside on the deck under tarpaulins.
With the dropped triglyphs, what is interesting is the fudging involved. With Giulio the triglyph and the section of entablature below has slipped. The architrave section has a slight taper, trying to convince us that the architrave is a straight arch consisting of multiple small pieces with sloping sides forming voussoirs. This is not very realistic, unless perhaps we consider it to be simply in relief, as it in fact is. Where a gap opens up at the top of the slipped triglyph (Fig. 8), Giulio actually tells us that the triglyph is quite shallow, resting against the wall behind and kept in place by the ‘flat arch’ architrave section. The triglyph is narrower than the architrave section, which means that there ought to be little square recesses above the architrave band, but Giulio, or later restorers, has ignored this or filled it in, which weakens the effect. I think I will restore these. The architrave section below is much deeper, and is slightly separated from the wall behind, to help cast a shadow and to heighten the viewer’s awareness of it as a true architrave (Fig. 9).
For the entablature to have slipped the architrave needs to have moved apart, but in practice things do not quite add up, especially on the right hand instance. Here the architrave block slopes at about 10 degrees and there is a gap which is filled at the bottom of the intact part of the architrave which forms prongs that seem to grip the slipped architrave and stop it slipping further (Fig. 10). As a result of all this the architrave band is significantly shorter than the space it supposedly once occupied, which is commensurate with the two halves of the architrave having moved apart. But there ought, therefore, to be corresponding gaps on either side of the triglyph slab. But this would imply gaps in the cornice above. In any case the idea of slipping — as opposed to splitting apart — is clearer if the triglyph fits tightly. Which brings us back to the architrave. If this had straight sides there would be nothing visually to stop it keep slipping, which is why the architrave has to be a flat arch. The whole slipping keystone motif is predicated on the idea of voussoirs, which is why the architrave needs it.