powerful conspiracy, and was joined by the Bardi, Rossi, Frescobaldi, Scali Altoviti, Magalotti, Strozzi, and Mancini.  Of the second, the principals were Manno and Corso Donati, and with them the Pazzi, Cavicciulli, Cerchi, and Albizzi.  Of the third the first was Antonio Adimari, and with him the Medici, Bordini, Rucellai, and Aldobrandini.  It was the intention of these last, to slay him in the house of the Albizzi, whither he was expected to go on St. John’s day, to see the horses run, but he not having gone, their design did not succeed.  They then resolved to attack him as he rode through the city; but they found this would be very difficult; for he was always accompanied with a considerable armed force, and never took the same road twice together, so that they had no certainty of where to find him.  They had a design of slaying him in the council, although they knew that if he were dead, they would be at the mercy of his followers.

While these matters were being considered by the conspirators, Antonio Adimari, in expectation of getting assistance from them, disclosed the affair to some Siennese, his friends, naming certain of the conspirators, and assuring them that the whole city was ready to rise at once.  One of them communicated the matter to Francesco Brunelleschi, not with a design to injure the plot, but in the hope that he would join them.  Francesco, either from personal fear, or private hatred of some one, revealed the whole to the duke; whereupon, Pagolo del Mazecha and Simon da Monterappoli were taken, who acquainted him with the number and quality of the conspirators.  This terrified him, and he was advised to request their presence rather than to take them prisoners, for if they fled, he might without disgrace, secure himself by banishment of the rest.  He therefore sent for Antonio Adimari, who, confiding in his companions, appeared immediately, and was detained.  Francesco Brunelleschi and Uguccione Buondelmonti advised the duke to take as many of the conspirators prisoners as he could, and put them to death; but he, thinking his strength unequal to his foes, did not adopt this course, but took another, which, had it succeeded, would have freed him from his enemies and increased his power.  It was the custom of the duke to call the citizens together upon some occasions and advise with them.  He therefore having first sent to collect forces from without, made a list of three hundred citizens, and gave it to his messengers, with orders to assemble them under the pretense of public business; and having drawn them together, it was his intention either to put them to death or imprison them.

The capture of Antonio Adimari and the sending for forces, which could not be kept secret, alarmed the citizens, and more particularly those who were in the plot, so that the boldest of them refused to attend, and as each had read the list, they sought each other, and resolved to rise at once and die like men, with arms in their hands, rather than be led like calves to the slaughter.  In a very short time the chief conspirators became known to each other, and resolved that the next day, which was the 26th July, 1343, they would raise a disturbance in the Old Market place, then arm themselves and call the people to freedom.