Notes:

He was slain by Hugh Campbell, Sheriff of Ayr at the instigation of Sir James Hamilton.
He succeeded as 2nd Earl of Cassillis in 1513. He was a prominent figure in the history of Scotland; Ambassador to England, a Privy-Councillor to James V, concluded truce with the Duke of Norfolk on part of Henry VIII after 1513.
He was invested as a Privy Counsellor (P.C.) [Scotland] to King James V. In 1525 he was tried for the murder of Martin Kennedy of Lochland in 1525, but was acquitted through the influence of his brother-in-law, the Earl of Argyll. In December 1526 he was a prisoner in the hands of the Douglas faction, after having joined the unsuccessful attempt of the Earl of Arran to rescue the young King James V. (http://www.thepeerage.com/p1224.htm#i24462)
Children:
Gilbert, 3rd Earl of Cassillis, m. Margaret Kennedy; b. between 1517 and 1518.
Thomas.
David of Culzean; m. Janet Kennedy, daughter of Duncan Kennedy of Daljedburgh.
Quintin, Abbot of Crossraguel who disputed three days at Maybole with Knox.
Archibald.
Hugh of Barquhany.
James of Uchtrelure.
(--?--); m. Thomas McClelland of Bombay.

Gilbert married Isabel CAMPBELL before 1513. Isabel was born about 1489; died after 1529. [Group Sheet] [Family Chart]

1. Gilbert KENNEDY was born in 1515 in Cassillis, Maybole, Ayrshire, Scotland; died on 28 Nov 1558 in Dieppe, Normandy, France; was buried in Maybole, Ayrshire, Scotland.

Notes:

David Kennedy had charters to lands and baronies of Cassillis, Dunure, Girvan, Glennop and Leswalt after 1508.
He was invested as a Knight on 29 January 1487/88 by King James III. He was invested as a Privy Counsellor (P.C.) [Scotland] to King James IV. He succeeded to the title of 3rd Lord Kennedy [S., 1457] between 24 July 1508 and 13 May 1509. He was created 1st Earl of Cassillis [Scotland] on 23 October 1509. He fought in the Battle of Flodden on 9 September 1513.
Children:
Gilbert, 2nd Earl of Cassillis, b. circa 1490; m. Lady Isabel Campbell.
William, Abbot of Crossraguel.
James of Brunston.
Thomas of Coiff.
Katherine; m. Quintin Mure; m. William Hamilton.
Christian; m. John Kennedy of Guiltree.

David married Agnes BORTHWICK before Jul 1489. Agnes was born before 1465 in Nenthorn, Lothian, Scotland. [Group Sheet] [Family Chart]

Notes:

He succeeded to the title of 2nd Lord Kennedy [S., 1457] circa 1480. He held the office of a Commissioner to treat with the English in 1484. He was invested as a Privy Counsellor (P.C.) [Scotland] to King James III. (http://www.thepeerage.com/p5464.htm#i109277)
Children:
David, 3rd Lord Kennedy, b. circa 1460; m. Agnes Borthwick.
Katherine; b. circa 1460; m. Thomas Kennedy, son of Gilbert Kennedy of Bargany, circa 1470.

John married Elizabeth MONGOMERIE after 25 Mar 1460. [Group Sheet] [Family Chart]

Notes:

He held the office of Keeper of the Castle of Lochdoun. He was created 1st Lord Kennedy [Scotland] between 27 March 1457 and 20 March 1458. In 1460 on the death of King James II, he was one of the six Regents of Scotland. He held the office of Constable of Stirling Castle in 1466.
Children:
John, b. circa 1436; m. Elizabeth Montgomerie.
James of Row; b. circa 1440; m. Egidia Blair after 1460.
Walter of Glentig; b. after 1440.
He was Parson of Douglas circa 1470.31
Catherine; b. circa 1450; m. Alexander Montgomery, 2nd Lord Montgomery, son of Alexander Montgomery 1st Lord Montgomery, circa 1470.
Mariot; b. circa 1450; m. Sir John Wallace of Craigie circa 1470.

Gilbert married Catherine MAXWELL after 1425. Catherine was born before 1408 in Linlithgow, Linlithgowshire, Scotland. [Group Sheet] [Family Chart]

Notes:

Name is also variously spelled "Katherine" on some genealogy data; however, I lean toward the older spelling of "Catherine," given the time in which she lived.