Unfortunately for the scheme, a day or two before the great stroke was to be hazarded, Cosmo de Pescarengis had been accidentally arrested for debt.  A subordinate accomplice, taking alarm, had then gone before the magistrate and revealed the plot.  Volmar and de Maulde fled at once, but were soon arrested in the neighbourhood.  President de Meetkerke, Professor Saravia, the preacher Van der Wauw, and others most compromised, effected their escape.  The matter was instantly laid before the States of Holland by the magistracy of Leyden, and seemed of the gravest moment.  In the beginning of the year, the fatal treason of York and Stanley had implanted a deep suspicion of Leicester in the hearts of almost all the Netherlanders, which could not be eradicated.  The painful rumours concerning the secret negotiations with Spain, and the design falsely attributed to the English Queen, of selling the chief cities of the republic to Philip as the price of peace, and of reimbursement for expenses incurred by her, increased the general excitement to fever.  It was felt by the leaders of the States that as mortal a combat lay before them with the Earl of Leicester, as with the King of Spain, and that it was necessary to strike a severe blow, in order to vindicate their imperilled authority.

A commission was appointed by the high court of Holland, acting in conjunction with the States of the Provinces, to try the offenders.  Among the commissioners were Adrian van der Werff, John van der Does, who had been military commandant of Leyden during the siege, Barneveld, and other distinguished personages, over whom Count Maurice presided.  The accused were subjected to an impartial trial.  Without torture, they confessed their guilt.  It is true, however, that Cosmo was placed within sight of the rack.  He avowed that his object had been to place the city under the authority of Leicester, and to effect this purpose, if possible, without bloodshed.  He declared that the attempt was to be made with the full knowledge and approbation of the Earl, who had promised him the command of a regiment of twelve companies, as a recompense for his services, if they proved successful.  Leicester, said Cosmo, had also pledged himself, in case the men, thus executing his plans, should be discovered and endangered, to protect and rescue them, even at the sacrifice of all his fortune, and of the office he held.  When asked if he had any written statement from his Excellency to that effect, Cosmo replied, no, nothing but his princely word which he had voluntarily given.

Volmar made a similar confession.  He, too, declared that he had acted throughout the affair by express command of the Earl of Leicester.  Being asked if he had any written evidence of the fact, he, likewise, replied in the negative.  “Then his Excellency will unquestionably deny your assertion,” said the judges.  “Alas, then am I a dead man,” replied Volmar, and the unfortunate deacon never spoke truer words.  Captain de Maulde also confessed his crime.  He did not pretend, however, to have had any personal communication with Leicester, but said that the affair had been confided to him by Colonel Cosmo, on the express authority of the Earl, and that he had believed himself to be acting in obedience to his Excellency’s commands.