In May the general assembled four hundred of his soldiers, Creek Indians under their chief Malachee, Cherokees under their chief Raven, at St. George Island, at the mouth of the St. Johns River. Oglethorpe's object was to cut off supplies from St. Augustine. His men crossed the river, and a body of Indians and a few white soldiers made an attack on the Spanish fort at San Diego. This place was defended by a number of large guns, and the first attack on it failed. Then Oglethorpe came up with the rest of his men and decided to try a little strategy. He ordered some of his soldiers to beat drums in different parts of the woods and other soldiers to march out at these places and march back again, the same soldiers appearing again and again. The Spanish garrison, seeing so many men at so many different points in the woods, soon concluded that the English had an overwhelming force in the field against them. Then Oglethorpe sent a Spanish prisoner he had captured to tell the garrison how well he had been treated. Thereupon the garrison surrendered to the English general.
The troops from Carolina had not yet arrived, and Oglethorpe learned that, while they delayed, two sloops filled with provisions and ammunition and six Spanish galleys had reached St. Augustine. On the eighteenth of May, however, two English ships anchored in the harbor and two others blocked the southern entrance to the Spanish port, and soon afterward a part of the troops from Carolina joined the general. He then gave the order to advance on the Spanish town.
St. Augustine was defended by 2,000 soldiers, quite as many as the troops Oglethorpe had marshaled against it. The Spanish artillery was vastly superior to that of the English. If the town was to be taken the sea forces must attack at the same time as the land forces, and signals were arranged for such a joint attack.
The general came to Fort Moosa, three miles from St. Augustine, and found the garrison had abandoned it. He gave orders to burn the gate there and make holes in the walls, "lest," as he said, "it might one day or other be a mouse-trap for some of our own people." Marching on, he gave the signal to attack the Spanish capital, but was surprised that the fleet gave him no answering signal. Later he learned that the Spaniards had deployed their ships in such a way that a sea attack would have been very difficult, and that the English commanders had decided that if they made the attack as agreed upon they would probably be defeated. Therefore the general determined that instead of an assault he would attempt a blockade.
He returned to Fort Diego, and ordered Colonel Palmer, with over two hundred Scotchmen and Indians to march to Fort Moosa and scout through the woods to prevent any communication between St. Augustine and the interior of Florida. Colonel Palmer was told to camp each night in a new place, to avoid battle, and to return at once if a larger force than his own appeared. Another officer was sent with the Carolina soldiers to take Point Quartell, which was about a mile distant from the castle of St. Augustine, and build a battery there to command the northern entrance to the harbor.
The general himself set out to capture the Spaniards' battery at Anastasia, and by clever maneuvers there succeeded in driving the enemy to their boats. Oglethorpe set up cannon and sent an envoy to the Spanish governor, calling on him to surrender. The Spaniard replied that he should be glad to shake hands with General Oglethorpe if the latter would come to him in his castle. In answer Oglethorpe opened fire from his new battery, but the distance to the town was too great for his guns and little harm was done the enemy.
Colonel Palmer, meantime, disregarding the general's orders to camp in a new place each night, had kept his men in the partly demolished Fort Moosa. The Spaniards sent six hundred men to attack his small force. Palmer's soldiers resisted desperately, but the Highlanders and the Indians were too much outnumbered by the Spaniards; half of them, including Colonel Palmer, were killed, a few escaped, and the rest were made prisoners.
The commander of the fleet also disregarded the arrangement he had made with Oglethorpe and ordered off the war-ship stationed outside the harbor, with the result that several sloops from Havana with new troops and provisions stole into the channel and reached the Spanish stronghold. The garrison at St. Augustine had begun to feel the pinch of hunger and might soon have surrendered, but these fresh supplies tided them over and enabled them to keep up their defense.
General Oglethorpe, discouraged in his plan of a blockade, decided to make one more attempt at carrying the town by assault. The British commodore, Pearse, was to attack with his fleet while Oglethorpe led his soldiers by land. The colonial troops and Indians were ready to open fire, and only waited the signal from the ships. They waited in vain, however. Instead of keeping his agreement, Commodore Pearse quietly sailed away with all his ships, sending word to General Oglethorpe that it was now the season when hurricanes might be expected off the Florida coast and that he didn't intend to risk His Majesty's fleet there any longer.
Oglethorpe, who alone seemed really in earnest in his desire to fight the Spaniards, deserted by the English fleet, getting very little support from the officers and men of the Carolina regiments, found it impossible to carry on the campaign. Even his own men from Georgia were worn out by fatigue and the heat of Florida. Reluctantly therefore he gave over his expedition, and returned to Savannah. The campaign, however, had shown the Spaniards that the governor of Georgia was a man whose power was to be respected, and they did not renew their raids into his province for some years.