It was apprehended, at this time, that the emperor Maximilian would enter Italy with an army; and its various states sent ambassadors to him, to make favourable terms. The emperor had applied to Florence for money; and the republic sent Francesco Vettori to treat concerning the sum. [Sidenote: 1507. Ætat. 38.] They afterwards sent Machiavelli with their ultimatum. Both ambassador and secretary remained some time at Trent, waiting on the imperial court. [Sidenote: 1508. Ætat. 39.] Machiavelli employed himself in making observations on the state of the country, which he reduced to writing, in a brief "Account of Germany," on his return. He had before drawn up a similar account of the state of France. The favourite object of Florence continued to be the reduction of Pisa. They purchased permission to attack it, from the kings of France and Spain, for a large sum of money. [Sidenote: 1509. Ætat. 40.] They besieged the town, dividing their army into three divisions, which blockaded it on three sides. The camps were each commanded by commissaries; and Machiavelli was sent thither to advise with and assist them. He passed from one camp to the other, to watch over the execution of the measures concerted for the siege; and, at one time, went to Piombino, to meet some deputies from Pisa, to arrange a treaty; but it came to nothing, and he returned to the army. He was much trusted by his government; and one of the commissaries, in writing to the signoria, observes, "Niccolò Machiavelli left us to-day, to review the troops of the other camp. I have directed him to return here, as you order; and I wish for nothing so much as to have him with me." After a blockade of three months, Pisa surrendered. The Florentine republic behaved with the greatest generosity and humanity, and kept terms faithfully with a people who had injured them deeply, and were now wholly at their mercy. Late in the same year, Machiavelli was employed to convey to Mantua the money composing a part of the subsidy of Florence to the emperor. After having discharged this office, he was ordered to repair to Verona, "or," as his instructions say, "wherever it seems best, to learn and communicate intelligence of the actual state of affairs. You will diligently write us word of every thing that happens worthy of notice, changing the place of your abode each day." That part of Italy was, at that time, the seat of a cruel and destructive war carried on between the emperor and the republic of Venice.