D) THE DRAWING OF G.A. DOSIO
It is extremely important the drawing of the architect Giovanni Antonio Dosio that shows in the lower part the fallen pier and arches and the sentence "Vestigie del Ponte S.Maria Ruinato p. la inondatione del Tevere l'anno 1557" [remains of the Bridge S.Maria fallen down due to the Tiber flood of 1557] (pict.4) and in the upper part the bridge at the end of the complete restoration dated 1575 in which it is visible the new pier with the base reinforced by means of a stepped breakwater and the two new arches with the sign of the pope Gregorius XIII (the dragons of the Boncompagni family) in the lunettes of the arches and at the top of them.
The Dosio's drawing represents the main proof that the bridge section fallen and rebuilt again and again was that one on Trastevere side instead of the opposite one as believed by many authors, misled also by the iconography, commonly k nown and represented in all the images and pictures of the bridge, showing it without the arches of the eastern side.
  The restoration, that had been final as that part of the bridge has arrived intact until nowadays throughout more than three hundred years till the erection of the embankments, was commemorated by means of two plaques located in opposite sides on the internal parapets of the second arch starting from the right bank; the one on the downstream side remained at it place until the demolition of the two arches on Trastevere side at the end of century XIX (pict.5). This was the text of the epigraph:

EX AVCTORITATE GREGORII XIII PONT. MAX
S.P.Q.R.
PONTEM SENATORIVM CVIVS FORNICES VETVSTATE
COLLAPSOS ET IAMPRIDEM REFECTOS FLVMINIS
IMPETVS DENVO DEIECERAT IN PRISTINAM
FIRMITATEM AC PVLCHRITVDINEM RESTITVIT
ANNO IVBILAEI MDLXXV

 [According to the will of pope Gregorius XIII the Rome Town Council in the jubilee year 1575 returned to the original soundness and beauty the Senatorius bridge whose arches, fallen down due to the old age and already previously restored, had been again knocked down by the river impetus]
In 1596, according to the will of the previous pope Sixtus V, Giacomo della Porta put under the cobbled surface of the bridge the aqueduct of the Felice water, that at last led the running water to Trastevere feeding, in particular, the fountain of S.Maria.