The Four Masters describe the route taken as having been from Limerick along the northern bank of the Shannon through Clare, the troops ferrying themselves across the river at Glin, but it is most likely that Sir George Carew’s biographer gives the correct line of march.
Captain Gawin Harvey’s ship, with the ordnance on board, had been anchored in the Shannon for fourteen days awaiting their arrival, and the guns were at once unshipped upon the arrival of the troops.
That night the forces entrenched themselves between the castle and the river, and the next day, under the guise of a parley, they managed to plant the cannon without opposition.
The next day the Knight of Glin, who was not within the castle, asked for a safe conduct to the English camp, which was granted. Upon arrival he demanded to see the President, but was refused unless upon an unconditional surrender. This he would not consent to, and was, therefore, ordered to depart. Seeing his son in the camp, whom he had delivered as a hostage some time previously, he seemed to hesitate, but as he still held out for terms the Earl of Thomond broke off the negotiations, and the Knight and his attendants retired to a neighbouring hill to watch the attack.
Later the Constable of the fortress sent a message to the Earl of Thomond begging an interview, which was granted. He began by stating that the love he bore the Earl, being a Thomond man himself, had induced him to warn the English to depart, as the Earl of Desmond with three thousand Connaught men were only two miles off, and would most likely attack the camp and drive them all into the river. The Earl laughed at his forebodings, and told him to deliver the castle and so save himself and the warders from death. This offer he refused, and the President, hearing he had done so, sent a message to say that he hoped to place his head on a stake in two days’ time.
One of the cannon becoming clogged, Sir George Carew ordered it to be filled with a charge in inverted order and the fire put to the mouth, so as to clear the touch-hole by the explosion. This was carried out with great success, much to the relief of the besiegers.
A fire of small shot was kept up from the castle at the ordnance, and the President, placing the Knight’s son on one of the cannon, sent a message to the garrison to say he had given them a mark to aim at. The Constable replied that the Knight of Glin might have more sons, and that the child should not deter him from firing.