Cardigan's overwhelming enthusiasm for the army remained and the meticulous standards of dress and parade that he had required of his earlier commands he now applied to the whole cavalry. He was made Colonel of the Regiment of the 5th Dragoon Guards in 1859, but he derived more satisfaction when, after his formal retirement in 1860, and its accompanying promotion to Lieutenant-General, he became colonel of his favourite regiment, the 11th Hussars, which he had first commanded in 1836. He remained in royal favour and early in 1861 he was selected to accompany the Prince of Wales, heir to the throne, to inspect Prussian cavalry manoeuvres. He was possibly an unwise choice as his arrogant behaviour towards his hosts, themselves no strangers to high self-esteem among military officers, resulted in numerous challenges to duel; he was quickly sent home. The Queen, however, blocked his colonelcy of one of the Household regiments because of his dalliance with Adeline while still married to Elizabeth. His last military function was a mounted review of the 11th Hussars before their embarkation for India in May 1866. He was joined by Colonel John Reynolds, who had been Cardigan's adversary in the "black bottle affair", but the men had at last settled their differences in the previous year.