=Cohort.= A division of the ancient Roman armies, consisting of about 600 men, divided into centuries. It was the tenth part of a legion, and its number, consequently, was under the same fluctuation as that of the legions. In the time of the empire the cohort often amounted to 1000 men. =Coif.= Was originally an iron skull-cap, worn by knights under their helmets; it was introduced before 1259. It is now especially applied in Great Britain to a cap worn by sergeants-at-law. =Coimbra.= An ancient city of Portugal, capital of the province of Beira. It appears to have been originally built by the Goths; from them it passed to the Moors, from whom it was finally conquered in 1064 by Fernando the Great, aided by the gallant Cid. It was taken by the troops under the British colonel Kent, October 7, 1810. =Coin= (Fr. _coin d’artilleur_). In gunnery, a kind of wedge to lay under the breech of a gun, in order to raise or depress the metal. Written also _quoin_. =Colberg=, or =Kolberg=. A strongly fortified seaport of Prussian Pomerania. It stands on a hill, surrounded with swamps which can be laid under water, and is chiefly remarkable for the protracted sieges it has undergone. In 1102, Duke Boleslaus, of Poland, besieged it in vain. It endured long sieges in the Thirty Years’ War and in the Seven Years’ War, and again in 1807, when it was most gallantly defended against the French. =Colchester.= The chief town in the county of Essex, England. It was taken from the Danes in 921 by Edward the Elder, who founded the castle. It was ravaged by the plague in 1348, in 1360, and again in 1665. In 1648 it was taken by Lord Goring for Charles I., but was retaken by Fairfax after a siege of 11 weeks, when the castle was dismantled. =Cold Harbor.= A village of Hanover Co., Va., about 10 miles northeast of Richmond. During the civil war a series of desperate struggles took place in and around this place (May 28-June 3, 1864) between the forces of Gens. Grant and Lee, resulting in a loss of probably 13,000 men on the Federal side. =Coldstream.= A border-town of Scotland, in Berwickshire, on the left bank of the Tweed. Near this place is the famous ford where the English and Scottish armies formerly crossed the Tweed. Here Gen. Monk raised the regiment still known as the Coldstream Guards. =Coldstream Guards.= A regiment in the Foot Guards, or Household Brigade, is the oldest corps in the British army except the First Foot. It was raised at Coldstream in 1660, by Gen. Monk, and was first called Monk’s regiment, but when Parliament consented to give a brigade of guards to Charles II., this corps, under its present name, was included in it. =College of Arms.= See HERALD’S COLLEGE. =Collet= (_Fr._). In gunnery, that part of a cannon which is between the astragal and the muzzle.