Cosimo busied himself in peaceful pursuits.  He greatly encouraged the arts and crafts, and set on foot sagacious reformation of the conditions and activities of the great Trade Guilds.  The College of Science was due to his patronage; and, in 1540, he extended his special protection to the Florentine Academy—­whence sprang the still more famous Accademia della Crusca.

Still due regard was paid to the exigencies of political peace and the maintenance of safeguards, Throughout Tuscany Cosimo raised forts and works of defence.  All the more important towns were fortified, and entrenched camps and bastions were erected at San Martino in Mugello, and at Terra del Sole.  He kept his hand upon the pulse of Florence:  no slackening of restraint was possible.  The men who had acclaimed him in 1537 were quite capable of crying out for his supersession at any time.  Fickle indeed were the Florentines ever, but in Cosimo they had a master who would not let them go.

The Duke’s family was growing fast, and each year as it passed gave him a precious hostage to love and to fortune.  The Duchess, in 1543, brought forth her fourth child, another boy, called Giovanni, after his grandfather, and in honour of good St John the Baptist, the patron saint of Florence.  Lucrezia followed in 1544, and then there came and went in 1545 and 1546 Antonio and Piero.  Garzia was born in 1547.  A year sped by, and in 1549, Ernando or Ferdinando, made his appearance and then came a barren season, and when, perhaps, it had been concluded that the Duchess had ceased child-bearing, came a great surprise, one more little son, in 1554, Piero was his name.

Meanwhile, Maria had been growing fast along with her many brothers and sisters.  At the age of eight or nine she was an attractive little damsel.  “Tall for her age, with a face not only pretty, but intelligent, and as merry and as full of life as was possible.  Her broad forehead was indicative of more than ordinary mental power.”  Her thirst for knowledge and her power of acquisition delighted her doting father and mother.

Maria was reared with all the care that love and hope could inspire, and at her mother’s knee she learned her first lessons.  The unhappy result of poor young Caterina’s education proved to Duke Cosimo that the convent was no place for her, and, although he placed Alessandro’s illegitimate little daughters, Giulia and Porczia, with the good nuns, he resolved that no such experience should be that of his own dear children.  The common saying, “The cow that is kept in the stall gives the best milk” had for him a special significance!