One of these exploits, carried out on Palm Sunday, the 19th of March 1307, with barbarities excessive even in those days, is known as the” Douglas Larder.” Douglas routed Sir John de Mowbray at Ederford Bridge, near Kilmarnock, and was entrusted with the conduct of the war in the south, while Bruce turned to the Highlands. In 1308 he captured Thomas Randolph (afterwards earl of Moray), soon to become one of Bruce’s firm supporters, and a friendly rival of Douglas, whose exploits he shared. He made many successful raids on tile English border, which won for him the dreaded name of the “Black Douglas” in English households. 

Through the capture of Roxburgh Castle in 1314 by stratagem, the assailants being disguised as black oxen, he secured Teviotdale; and at Bannockburn, where he received the singular honour of being created a Knight banneret by the king, Robert the Bruce, a distinction only ever conferred on the battlefield.  He commanded the left wing with Walter the Steward. During the thirteen years of intermittent warfare that followed he repeatedly raided England. He slew Sir Robert de Nevill, the ‘ Peacock of the North,” in. single combat in 1316, and in 1319 be invaded Yorkshire, in company with, Randolph, defeating an army assembled by William do Melton, archbishop of York, at Mitton-on-Swale (September 20), in a fight known as “The Chapter of Myton.” 

In 1322 he captured the pass of Byland in Yorkshire, and forced the English army to retreat. He was rewarded by the “Emerald Charter,” granted by Bruce, which gave him criminal’~ jurisdiction over the family estates, and released the lords of Douglas from various feudal obligations. 

The emerald ring which Bruce gave Douglas in ratification of the charter is lost, but another of the king’s gifts, a large two-handed sword (bearing, however, a later inscription), exists at Douglas Castle. In a daring night attack on the English camp in Weardale in 1327 Douglas came near capturing Edward III. himself. 

After laying waste the northern counties he retreated, without giving battle to the English. Before his death in 1329 Bruce desired Douglas to carry his heart to Palestine in redemption of his unfulfilled vow to go on crusade. Accordingly Sir James set out in 1330, bearing with him a silver casket containing the embalmed heart of Bruce. He fell fighting with the Moors in Spain on. the 25th of August of that year, and was buried in St Bride’s Church, Douglas. Since his day the Douglases have borne a human heart in their coat of arms. Sir James was said to have fought in feventy battles and to have conquered in fiftyseven. 

His exploits, as told in Froissart’s Chronicles and in John Barbour's Bruce> are familiar from Scott's Tales of a Grandfather and Castle Dangerous. His half-brother, Sir Archibald, defeated Edward Baliol at Annan in 1332, and had just been appointed regent of Scotland for David II. when he risked a pitched battle at Halidon Hill, where he was defeated and killed (1333), with his nephew William, lord of Douglas. The inheritance fell to his brother, a churchman, Hugh the "Dull" (b. 1294), who surrendered his lands to David II.; and a re-grant was made to William Douglas, next referred to.

Source: http://20.1911encyclopedia.org/D/DO/DOUGLAS_EARLS_OF.htm 

Second version:

Douglas, James (Sir) "Good James (Sir)/Black Douglas" b. 1286. d. August 25, 1330.
James of Douglas was the friend and ablest lieutenant of Robert the Bruce. Known as the Black Douglas to the English and as the Good James (Sir) to the Scots, Douglas was a brilliant fighter and master of guerrilla warfare. He commanded the left wing of Bruce's army at the battle of Bannockburn. Before his death, Bruce asked Douglas to take his heart on a crusade to the Holy Land. Douglas set out bearing Bruce's heart in a silver casket, but on the way fell fighting the Moors in Spain. The Scottish knights who survived brought back Douglas's body which was entombed in the town of Douglas and Bruce's heart which was buried in Melrose Abbey.
St Bride's Kirk, Douglas, Lanarkshire, Scotland.
Cause of Death: killed in battle with the Moors."

Father: William (le Hardi) 5th of Douglas
Mother: Elizabeth Steward

Marriage 1 Spouse Unknown

1. Archibald the Grim (3rd Earl of Douglas) Douglas b: ABT. 1320

Source: http://worldconnect.rootsweb.com/cgi-bin/igm.cgi?op=GET&db=maclaren&id=I10682

He was amongst the SIGNATORIES OF THE DECLARATION OF ARBROATH (1320)

Source: http://www.stirnet.com/HTML/genie/individuals.htm#dd 

This pewter model is part of Nigel Tranter's Bannockburn Limited Edition Chess Set. This specially devised and commissioned by Morag and John Morgan exclusively for Cornerstone.

See also article on a painting of the Black Douglas