Note that sources don't always agree so please excuse any errors!

Records of Irvines in Scotland - with many different spellings including Irwyn, Irving, Irwin, Ervin, Erwin, Irvin, Urwin and more - date to between 1124 and 1165. The family claims origins from the High Kings of Ireland and through them to Scotland’s early Celtic Kings. The first daughter of Malcolm II (King of Alba from 1005) married Crinan Eryvine; as Malcolm had no male heirs, their son Duncan (Donnchad mac Crinain) became Duncan I on his grandfather’s death in 1034. In 1040 Duncan was defeated by invading Norsemen and while leading the remains of his army home was murdered by his cousin Mac Bethad mac Findláich (MacBeth). Shakespeare's play "MacBeth" is based around Duncan's murder.
Drum Castle in Aberdeenshire became the seat of the Irvines of Drum in 1323 when Robert the Bruce awarded William de Irwyn the barony of Drum, including lands and the already existing Tower of Drum (built as a royal hunting lodge). Drum Castle grew from the Tower, with William as the first Baron of Drum.
William was born the 2nd son of Irving of Bonshaw in Dumfriesshire, who helped The Bruce evade capture by Edward 1 several times. William went into Bruce's service, was with him when he was routed at Methven, shared many later dangers and was one of the seven who hid with him in a copse of holly while his pursuers passed by. 10 years after the Battle of Bannockburn, William received the Barony and was permitted use of The Bruce’s private badge of three holly leaves, with the motto “Sub sole sub umbra virens” (Flourishing in both sunshine and shade), which are still on the arms of the Irvine/Irving Clans.
An influential Clan, the Irvines of Drum were involved in many other rivalries and political events over the centuries, including:
. An ongoing feud with Clan Keith escalated into a full war in 1402 at the battle of Drumoak where the Irvines under Alexander (3rd Laird of Drum) slaughtered the Keith army. The feud was not fully settled for hundreds of years – the reconciliation is detailed a bit later.
. The same Alexander was a knight of great prowess having also fought in wars in France. At the Battle of Harlaw in 1411 he engaged in single combat with the famous Hector Maclean of the Battles, chief of the Clan Maclean - both died from the wounds they inflicted on each other.
. During the Civil War (1642 – 1651) the royalist Irvines supported Charles I. As Drum Castle was in a Covenanter area, it was attacked and sacked several times.
. During the Jacobite rising of 1715, the 14th Laird of Drum (Alexander) supported the Jacobite cause and fought at the Battle of Sheriffmuir.
. In the 1745 Jacobite rising the 17th Laird (another Alexander), fought with the Jacobites at Culloden in 1746. Like many other prominent Jacobites he was hunted by Cumberland, hiding in a secret chamber in his castle, then fleeing to France. He was later allowed to return to his estate.
More recent events:
The twenty-second Baron of Drum (another Alexander) fought in the Grenadier Guards during World War I and was seriously wounded in 1916. He died in 1922, succeeded by his son Alexander who died young and had never married. The title passed to the second son, Quentin who became the 24th Laird. He also served in the military, fighting in East Africa during World War 2. Quentin died in 1975 and bequeathed the castle of Drum and its 300 acres of land to the National Trust for Scotland which now manages it and opens it to the public.
The Barony passed to another brother, Col. Charles Irvine M.C. and on his death in 1992 the title passed to David Irvine, who thus became the 26th Baron and Chief of Clan. In 2002, David Irvine met with the 13th Earl of Kintore, Chief of Clan Keith to sign a formal peace treaty between their Clans - an elaborate ceremony on the banks of the River Dee, 600 years after their major battle at Drumoak back in 1402.
The current Clan Chief is Alexander Irvine of Drum, who became 27th Baron of Drum in 2019.