In September the regiment was suddenly ordered to prepare for foreign service; two troops were separated to form a depôt; and eight troops, having given up their horses, sailed from Spithead, on the 5th of October, for South America, to engage in hostilities against the Spanish provinces in that part of the world. Entering the splendid and capacious harbour of Rio de Janeiro, the capital of Brazil, information was received of the re-capture of Buenos Ayres by the Spaniards; but arrangements, were, nevertheless, made for carrying on the war in the Spanish dominions in South America, and the SEVENTEENTH, having only short carbines, were ordered to be armed with Spanish muskets, and to serve as infantry. Leaving Rio de Janeiro, the fleet sailed to the Rio de la Plata; two hundred miles up this immense river stands the city of Buenos Ayres, where the stream is about thirty miles broad; but an attack on this place was deferred, and the commander of the expedition, Brigadier-General Samuel Auchmuty, resolved to proceed against _Monte Video_, a town situate in a small bay on the north side of the river, one hundred and twenty miles from Buenos Ayres. [Sidenote: 1807] In the middle of January, 1807, a landing was effected nine miles from Monte Video, and the army advanced towards that fortress, when the column, composed of the SEVENTEENTH, four troops of the Twentieth, and two of the Twenty-first Light Dragoons, was attacked by the enemy. Some sharp fighting occurred; Brigadier-General Auchmuty's charger was killed, and he mounted one of Lieut.-Colonel Lloyd's horses; his orderly trumpeter, Thomas Hudson, had also his horse killed under him; but eventually the British dragoons drove back their opponents, and took up the first position before the fortress, about two miles from the citadel. On the 20th of January a numerous body of men sallied from the town, but were driven back, and on the 22nd a number of the enemy approached the rear of the British line, when a skirmish ensued, in which the SEVENTEENTH had two men killed and three wounded. During the siege the SEVENTEENTH were employed in covering the troops before the town and in bringing up provisions, in the performance of which service they took many prisoners, and Lieut.-Colonel Lloyd received the personal thanks of Brigadier-Generals Auchmuty and Lumley. The town was taken by storm on the 3rd of February; on this occasion the SEVENTEENTH formed part of the division under Brigadier-General Lumley, in readiness to cover and support the attack, and to protect the rear; on the capture of the town the citadel surrendered.