The arsenal, which was famous in Dante's day, received its first enlargement in 1304, when, on the design of Andrea Pisano, new building sheds and the rope walk or Tana were erected.
The building, erected in the Italian Gothic style between 1278 and 1283, by Giovanni Pisano, is of special interest chiefly for its famous frescoes.
In the year 1278 they had entrusted the erection of their fine Campo Santo to Niccola and Giovanni Pisano, by whom the architectural part of it was completed towards the end of the century.
When the Genoese appeared off Meloria the Pisans were lying in the river Arno at the mouth of which lay Porto Pisano the port of the city.
In the 13th century the Pisans tried to attract a population to the spot, but it was not till the 14th that Leghorn became a rival of Porto Pisano at the mouth of the Arno, which it was destined ultimately to supplant.
In the early development of architecture and sculpture Pistoia played a very important part; these arts, as they existed in Tuscany before the time of Niccola Pisano, can perhaps be better studied in Pistoia than anywhere else; nor is the city less rich in the later works produced by the school of sculptors founded by Niccola.
During the 13th and 14th centuries in Italy the widespread influence of Niccola Pisano and his school encouraged the sculptor to use marble rather than bronze for his work.
The cathedral of St Januarius, occupying the site of temples of Apollo and Neptune, and still containing some of their original granite columns, was designed by Nicola Pisano, and erected between 1272 and 1316.