Colonel-in-Chief is a ceremonial position in a military regiment. It is in common use in several Commonwealth armies, where it is held by the regiment's patron, usually a member of the royal family. The position was formerly used in the armies of several European monarchies. A Colonel-in-Chief has a purely ceremonial role in their regiment.
The Norwegian Army has taken a more whimsical approach to the position, appointing the penguin Sir Nils Olav as a Colonel-in-Chief.
Historically a Colonel-in-Chief was the ceremonial head of a regiment, usually a member of a European country's royal family. The practice extends at least back to 1740 in Prussia when Frederick II held that position in the newly created Garde du Corps, an elite heavy cavalry regiment.
By the late 19th Century the designation could be given to the children of royalty; pictures exist of the daughters of Russian Czar Nicholas II in the uniforms of their regiments. The German Kaiser Wilhelm II carried the title to an extreme, holding it in literally dozens of German and (by diplomatic courtesy) Austro-Hungarian, British, Russian, and Portuguese regiments. In addition, his mother, wife, son, and daughters were also full or deputy Colonels-in-Chief of various units.
In modern usage, the Colonel-in-Chief of a regiment is its (usually royal) patron, who has a ceremonial role in the life of the regiment. They do not have an operational role, or the right to issue orders, but are kept informed of all important activities of the regiment and pay occasional visits to its units. The chief purpose of the Colonel-in-Chief is to maintain a direct link between the regiment and the royal family. Some artillery regiments have a Captain-General instead of a Colonel-in-Chief, but the posts are essentially the same.