Valentina Visconti, daughter of the late duke, who had died without male issue. As the son-in-law of Filippo, Francesco Sforza also deemed himself justified in aspiring to the throne of Milan.[375] In the mean time the inhabitants of that city, rejecting the pretensions of all the competitors, declared for independence, and instituted a republican form of government. The infant commonwealth was, however, doomed to struggle with unconquerable difficulties. Whilst it was harrassed by the Venetians, its strength was enfeebled by the anarchy of faction. After suffering a variety of calamities in the course of a protracted siege, the inhabitants of Milan were, in the year 1450, compelled by famine to open their gates to Sforza, who on the twenty-fifth of March, solemnly assumed the ducal diadem.[376] In the midst of these hostile operations, Nicolas had the prudence and the skill to observe a strict neutrality, and thus to secure to the ecclesiastical territories the blessings of public tranquillity. In the contemplation of the growing prosperity of his subjects the pontiff found an ample reward for his anxious endeavours to promote their welfare. The flourishing state of his finances, the consequence of his cultivation of the arts of peace, was also a source of considerable satisfaction to him, as it furnished him with the means of gratifying his passion for the encouragement of learning. Fostered by his patronage, the scholars of Italy no longer had reason to complain that they were doomed to obscurity and contempt. Nicolas invited to his court all those who were distinguished by their proficiency in ancient literature; and whilst he afforded them full scope for the exertion of their talents, he requited their labours by liberal remunerations.