The whole platform, or step, upon which all these designs are inlaid had been bordered, along the top and bottom, by a delightful frieze of _putti_, executed in 1423, by Agostino di Niccolo of Siena,[91] and Bastiano di Corso of Florence.[92] Of the former artist we know but little, but of the work of the latter, in company with his son Corso, on the pavement before the Cathedral doors, we find several notices, to which I have referred already,[93] A notice, dated 25th March, 1447,[94] speaks of other frieze-work done by father and son, “_sotto la tribuna di verso l’altare di Santa Chaterina_.” This work appears to have perished, or been superseded, unless, as is by no means impossible or improbable, we may attribute to him the frieze round the _Massacre of the Innocents_ described above, the authors of which are unknown and unidentified. Agostino and Bastiano’s frieze is a very graceful one, but it would seem, judging from the dates of the documents, as if the latter artist had succeeded the former in the work: for the first document speaks of payment made to Agostino up to December 30th, 1423, whereas both those commissioning Bastiano are dated the same month, with no allusion to previous or contemporary employment of any other artist. Three more steps bring us to the passage which runs round behind the altar. Here originally was some of the oldest work, but to all appearance now it would seem to be almost the most modern. In five circles we find the five Cardinal Virtues, the first of whom is _Fortitude_ (No. 21). On this spot, as I have already said in my first chapter, Marchesse d’Adamo[95] and his companions, the Comacene sculptors at work in Siena in 1406, are generally supposed to have executed the earliest figure-subject on the Pavement, about which we now possess authoritative information. There is nothing, however, to show their work. The figure is imposing and dignified in composition, but the workmanship on it is poor and somewhat paltry. Of the four other Virtues, _Justice_, _Christian Piety_, _Prudence_, and _Temperance_ (Nos. 20, 19, 18, and 17), there is little definite to be said. Padre Micheli[96] following Milanesi[97] gives 1406 as the possible date of the two first, 1380 as that of the other two; but there is nothing in their present condition to prove either one date or the other. The only thing that may be noticed is that the restoration of _Justice_ and _Prudence_ shows more vigour of conception and boldness of line, with far more satisfactory results than have been shown in the case of _Fortitude_ and _Temperance_. _Fortitude_, we know, was restored in 1839, and _Temperance_ perhaps at the same time. _Christian Piety_ is half covered by the great lectern, and so obliterated by the feet of readers and singers as to be now almost indistinguishable. The frieze of ladders (_scaglioni_) and thorns (_spini_), surrounding these works, is said to have been executed in 1406.[98]