Not only the Gonzagas, but several other ancient ducal families, died out about the date which we have reached.
The duke rounded off his dominions by the purchase of Tenda and Oneglia, which increased his seaboard, and the last years of his life were spent in fruitless negotiations to obtain Monferrato, held by the Gonzagas under Spanish protection, and Saluzzo, which was a French fief.
The Castello di Corte here, the old castle of the Gonzagas (1395-1406), erected by Bartolino da Novara, the architect of the castle of Ferrara, now contains the archives, and has some fine frescoes by Mantegna with scenes from the life of Ludovico Gonzaga.
But after a period of internal discord Ludovico Gonzaga attained to power (1328), and was recognized as imperial vicar (1329); and from that time till the death of Ferdinando Carbo in 1708 the Gonzagas were masters of Mantua (see Gonzaga).
In 1536 it passed to the Gonzagas of Mantua, who fortified it very strongly.