The first documented mention of the militia project in Machiavelli's correspondence occurred in a letter of 29 May 1504 from his friend Francesco Soderini, the cardinal of Volterra and the brother of the gonfalonier Piero Soderini.
Although Machiavelli's idea cannot have displeased Piero Soderini, who already back in 1502 had sharply criticized the mercenary troops' general lack of commitment, (22) the gonfalonier's cautious nature appears to have constituted a major impediment for its realization.
the Gonfalonier began, with the authority of the signoria, but without consultation, to enroll soldiers in the contado...
If it is helped along as is its due, I judge that it will turn out to be a wonderful thing and I shall be very happy when I see it completed, both for the good of the public and also because it is your invention." (35) Around this time, Machiavelli wrote to Cardinal Soderini exhorting him to persuade his brother, the gonfalonier, to place a forceful and severe military captain in command of the militia.
Although His Lordship the Gonfalonier understands public necessity and is exerting every effort to that end, nevertheless, stimulated by your writing, we recall at present a nd shall not cease to recall in the future what you write about it, which we still judge to be necessary.
In his reply to Machiavelli of 4 March, the cardinal promised to intercede with his brother, the gonfalonier, on his behalf concerning the militia.
But since the cardinal on this occasions acted as an intermediary between Machiavelli and the gonfalonier, it seems reasonable to assume that the example of Manlius originated from Machiavelli's lost letter of February-March 1506.
Writing to the gonfalonier, with Machiavelli's letter in front of him, the Cardinal simply passed on Machiavelli's comments on the need of a firm rule in the city and the contado and his advice to place a "severe and rigid" captain, similar to Manlius torquatus, at the head of the militia.