Piazza della Rotonda (right in front of the Pantheon) the fountain that Pope Eugene IV (1431-47) had done his best to decorate with a porphyry tub and two basalt lions. Here, della Porta, “the fountain architect of the Roman People”, designed a model of the fountain that was one of the best examples of fountains that combined the circular and rectangular designs – that is to say, those that paid greater regard to the relative proportions. This fountain is shaped as a square whose sides have been cut into slightly short of the corners, continuing as projecting semi-circles. The same fluid motif is repeated in the travertine steps (also by Sormani) below the fountain; you will notice that, owing to the uneven ground, there are five steps in front of the Pantheon and only two on the opposite side. The measurements for the fountain basin set out in the document were “in length 40 hands approx. [= 9m] and the same in width, or a little smaller; the circumference of the fountain to be around a hundred and twenty hands [= 27m] including projections, turns, heights and lengths”. The intended material was “mixed portasanta” marble but the water basin was made instead from a superb African marble, dull grey in color, so beautiful that it seems it must have been very important to whoever ordered it for this specific fountain.