He was not called upon to fulfil his promise to aid in the defence of Rhodes, for the death of Mahomet just at the time when he was preparing a vast expedition against it, freed the Island for a long time from fear of an invasion. From time to time they received visits from Ralph Harcourt, who, after five years longer service at Rhodes, received a commandery in England. He held it a few years only, and then returned to the Island, where he obtained a high official appointment.
In 1489 Sir John Boswell became bailiff of the English langue, and Sir Fabricius Caretto was in 1513 elected grand master of the Order, and held the office eight years, dying in 1521.
When, in 1522, forty-two years after the first siege, Rhodes was again beleaguered, Gervaise, who had, on the death of the countess, become Count of Forli, raised a large body of men-at-arms, and sent them, under the command of his eldest son, to take part in the defence. His third son had, at the age of sixteen, entered the Order, and rose to high rank in it.
The defence, though even more obstinate and desperate than the first, was attended with less success, for after inflicting enormous losses upon the great army, commanded by the Sultan Solyman himself, the town was forced to yield; for although the Grand Master L’Isle Adam, and most of his knights, would have preferred to bury themselves beneath the ruins rather than yield, they were deterred from doing so, by the knowledge that it would have entailed the massacre of the whole of the inhabitants, who had throughout the siege fought valiantly in the defence of the town. Solyman had suffered such enormous losses that he was glad to grant favourable conditions, and the knights sailed away from the city they had held so long and with such honour, and afterwards established themselves in Malta, where they erected another stronghold, which in the end proved an even more valuable bulwark to Christendom than Rhodes had been. There were none who assisted more generously and largely, by gifts of money, in the establishment of the Order at Malta than Gervaise. His wife, while she lived, was as eager to aid in the cause as he was himself, holding that it was to the Order she owed her husband. And of all their wide possessions there were none so valued by them both, as the little coral heart set in pearls that she, as a girl, had given him, and he had so faithfully brought back to her.