Following Rafael Giron, he served in the Diego Flores Valdés navy, which sailed to the Strait of Magellan, aboard the frigate Santa Catalina.

He was accused of disobedience and was sentenced to death by hanging by the Major General of the fleet, Francisco Arias de Bobadilla.

Cuéllar kept drifting in and out of consciousness; at one point he and his fellow survivor were discovered by two armed men, who covered them with rushes before going to the shore to loot.

Heeding the boy's warning not to approach the village, de Cuéllar limped past and went on his way alone, living off berries and watercress.

He was set upon by a group of men who beat him hard and stripped him of his clothes; he covered himself with a skirt of plaited ferns and rushes.

Having stayed some time at the settlement, the group met a young man who spoke Latin and directed them to the territory of Sir Brian O'Rourke in present-day County Leitrim.

In O'Rourke's country they found greater safety, at "a village belonging to better people, Christian and kindly", where 70 Spaniards were enjoying refuge.

Giving thanks to God that it had not gone even worse with me than to be gipsy among the savages, I began to look at the hands of each, and to say to them a hundred thousand absurdities, which pleased them so much that there was no other Spaniard better than I, or that was in greater favour with them.

By night and by day men and women persecuted me to tell them their fortunes, so that I saw myself (continually) in such a large crowd that I was forced to beg permission of my master to go from his castle".

He reckoned that, were it not for their hospitality, he and his fellows would not have lived: "As to ourselves, these savages liked us well because they knew we came against (to oppose) the heretics, and were such great enemies of theirs; and if it had not been for those who guarded us as their own persons, not one of us would have been left alive.

In November 1588 Cuéllar moved on to the territory of the MacClancy with 8 other Spaniards, staying at one of the lord's castles, probably at Rosclogher, on the south of Loch Melvin.

During that time they were unable to cross the boggy terrain and, having had their offer of safe passage to Spain turned down, they hanged two Spaniards in full view of the castle so as to terrorise the defenders.

MacClancy returned and bestowed gifts on the defenders, including an offer to Cuéllar of the hand of his sister in marriage, which was declined.

They sought out the bishop of Derry, Redmond O'Gallagher, and found he had twelve other Spaniards in his care, whom he intended to assist in a crossing to Scotland.

Cuéllar had heard the Scottish king "protected all the Spaniards who reached his kingdom, clothed them, and gave them passages to Spain".