He entered the service at an eventful moment. Napoleon had attained the zenith of his marvellous career. He was the virtual master of the whole of continental Europe. The royal family of Spain were in effect his prisoners, and his brother Joseph had been proclaimed King of Spain. The royal family of Portugal had departed to the New World lest worse things should befall it, and Junot was ruling in Lisbon in the name of his imperial master. But the Spaniards rose _en masse_ in a national insurrection; and no sooner had they raised the standard of independence than they felt the necessity of applying to England for aid. Almost simultaneously the Portuguese rose, and no severity on Junot's part availed to crush the universal revolt. Almost on the very day on which young Campbell joined his regiment in the Isle of Wight, the British force of nine thousand men to the command of which Sir Arthur Wellesley was appointed, sailed from Cork for the Peninsula. Spencer's division joined Wellesley in Mondego Bay, and on the night of the 8th of August 1808 thirteen thousand British soldiers bivouacked on the beach--the advanced guard of an army which, after six years of many vicissitudes and much hard fighting, was to expel from the Peninsula the last French soldier and to contribute materially to the ruin of Napoleon.
Campbell was posted to the second battalion of the Ninth, commanded by Colonel Cameron, an officer of whom he always spoke with affectionate regard. The first battalion of the regiment had already sailed from Cork, and the second, which belonged to General Anstruther's brigade, took ship at Ramsgate for the Peninsula on July 20th. Reaching the open sandy beach at the mouth of the Maceira on the 19th of August, it was disembarked the same evening, and bivouacked on the beach. Campbell notes, "lay out that night for the first time in my life;" many a subsequent night did he lie out in divers regions! On the following day the battalion joined the army then encamped about the village of Vimiera. Wellesley had only landed on the 8th, but already he had been the victor in the skirmish of Obidos and the battle of Roleia; and now, on the 21st, he was again to defeat Junot on the heights of Vimiera.