He states that he was married when he was twenty-one, and that the marriage took place in England, so that he must have returned home somewhere about 1813. But we really know nothing authentic of his movements till 1822, when he was in England, and thence went to Italy, where he made acquaintance with Lord Byron and with Shelley. After the lamentable death of the latter poet he attended at the cremation of the body. Thence he went with Byron to Greece in the Hercules, to aid the Greeks against the Turks. They arrived at Cephalonia, off the west coast, in the beginning of August, 1823, and there Lord Byron resolved on staying till he could ascertain how things were progressing in Greece and decide on his future course of action. This delay did not at all suit the impetuosity of the character of Trelawny, who called it dawdling, and set forward for the mainland in company with Hamilton Browne, making his way to the seat of the Greek Government. He also sent emissaries to England to endeavour to raise a loan, and then proceeded to Athens. Here the insurgent leader Odysseus was in command, and to his fortunes Trelawny at once attached himself, and married the sister of the Greek chieftain.
Major Temple, resident at Santa Maura, during his mission to the Morea in June, 1824, met Odysseus, and described him as "a perfect Albanian chieftain—savage in manners and appearance, of great muscular strength, and about six feet high."
He had his head-quarters in a huge cavern in the face of the limestone precipices of Mount Parnassus, which he had strongly fortified, and in this he kept his treasure that he had accumulated and lodged his family. In the meantime dissension had broken out among the Greeks, between the leaders of the bands that did all the fighting, under Kolokotroni, and the Executive Government that had been elected by the primates, at the head of which stood Mavrocordato. A complete rupture had ensued at the end of 1823 between the parties, and the guerilla chieftains absolutely refused obedience to the Provisional Government.
In the same winter of 1823-4 Trelawny accompanied Odysseus as aide-de-camp upon an expedition into Negropont, and on their return to Athens, where Colonel Stanhope then was, Trelawny sent a letter to his mother, of which the following is an extract:—
"Athens, 18th February, 1824.
"Dear Mother,—I am enabled to keep twenty-five followers, Albanian soldiers, with whom I have joined the most enterprising of the Greek captains and most powerful—Ulysses. I am much with him, and have done my best during the winter campaign, in which we have besieged Negropont, to make up for the many years of idleness I have led. I am now in my element, and the energy of my youth is reawakened. I have clothed myself in the Albanian costume and sworn to uphold the cause.
"Everything here is going on as well as heart can wish. Great part of Greece is already emancipated. The Morea is free, and we are making rapid progress to the westward. Lord Byron spends £5000 a year in the cause and maintains five hundred soldiers. This will in the eyes of the world redeem the follies of youth.
"Your affectionate son,
"Edward Trelawny."
Trelawny and Odysseus desired to get Lord Byron to be with them, but this plan was frustrated by the death of the poet on April 19th, 1824.
Colonel Stanhope proposed a congress of the civil and military leaders, so as to effect a reconciliation between the two embittered elements that were weakening the resistance against the common enemy, the Turk. Odysseus consented to attend this meeting at Salona, and Trelawny also agreed to be present. Mavrocordato looked on Trelawny with suspicion as intimate with Odysseus and as his brother-in-law, and he foisted upon him an English spy named Fenton, and an accomplice of the name of Whitcombe, with secret instructions to make away with him.
After returning from Salona, Trelawny was with Odysseus in Eastern Greece, carrying on the war in guerilla fashion without any great results.
In the autumn he was at Argos, whence a letter (certainly his, though unsigned) was sent to his brother Lieutenant Harry Trelawny, r.n.