Royal Regiment of Scotland in the context of British Army incremental infantry companies

Edinburgh Castle (Scottish Gaelic: Caisteal Dhùn Èideann) is a historic castle in Edinburgh, Scotland. It stands on Castle Rock, which has been occupied by humans since at least the Iron Age. There has been a royal castle on the rock since the reign of Malcolm III in the 11th century, and the castle continued to be a royal residence until 1633. From the 15th century, the castle's residential role declined, and by the 17th century it was principally used as a military garrison. Its importance as a part of Scotland's national heritage was recognised increasingly from the early 19th century onwards, and various restoration programmes have been carried out over the past century and a half.

Edinburgh Castle has played a prominent role in Scottish history, and has served variously as a royal residence, an arsenal, a treasury, a national archive, a mint, a prison, a military fortress, and the home of the Honours of Scotland – the Scottish regalia. As one of the most important strongholds in the Kingdom of Scotland, the castle was involved in many historical conflicts from the Wars of Scottish Independence in the 14th century to the Jacobite rising of 1745. Research undertaken in 2014 identified 26 sieges in its 1,100-year history, giving it a claim to having been "the most besieged place in Great Britain and one of the most attacked in the world". Few of the present buildings pre-date the Lang Siege of 1573, when the medieval defences were largely destroyed by artillery bombardment. The most notable exceptions are St Margaret's Chapel from the early 12th century, which is regarded as the oldest building in Edinburgh, the Royal Palace, and the early 16th-century Great Hall. The castle is the site of the Scottish National War Memorial and the National War Museum. The British Army is still responsible for some parts of the castle, although its presence is now largely ceremonial and administrative. The castle is the regimental headquarters of the Royal Regiment of Scotland and the Royal Scots Dragoon Guards and houses their regimental museums, along with that of the Royal Scots.

The Royal Scots Fusiliers was a line infantry regiment of the British Army that existed from 1678 until 1959 when it was amalgamated with the Highland Light Infantry (City of Glasgow Regiment) to form the Royal Highland Fusiliers (Princess Margaret's Own Glasgow and Ayrshire Regiment) which was later itself merged with the Royal Scots, King's Own Scottish Borderers, the Black Watch (Royal Highland Regiment), the Argyll and Sutherland Highlanders and the Highlanders (Seaforth, Gordons and Camerons) to form a new large regiment, the Royal Regiment of Scotland.

The Most Ancient and Most Noble Order of the Thistle is an order of chivalry associated with Scotland. The current version of the order was founded in 1687 by King James VII of Scotland, who asserted that he was reviving an earlier order. The order consists of the sovereign and sixteen knights and ladies, as well as certain "extra" knights (members of the British royal family and foreign monarchs). The sovereign alone grants membership of the order; they are not advised by the government, as occurs with most other orders.

The order's primary emblem is the thistle, the national flower of Scotland. The motto is Nemo me impune lacessit (Latin for "No one provokes me with impunity"). The same motto appears on the Royal coat of arms of the United Kingdom for use in Scotland and pound coins minted in 1984, 1989, 1994, and 1999 (since withdrawn), and is also the motto of the Royal Scots Dragoon Guards, the Scots Guards, the Royal Regiment of Scotland, and the Black Watch (Royal Highland Regiment) of Canada. The patron saint of the order is St Andrew.

The Royal Scots (The Royal Regiment), once known as the Royal Regiment of Foot, was the oldest and most senior infantry regiment of the line of the British Army, having been raised in 1633 during the reign of Charles I. The regiment existed continuously until 2006, when it amalgamated with the King's Own Scottish Borderers to become the Royal Scots Borderers, which merged with the Royal Highland Fusiliers (Princess Margaret's Own Glasgow and Ayrshire Regiment), the Black Watch, the Highlanders (Seaforth, Gordons and Camerons) and the Argyll and Sutherland Highlanders to form the Royal Regiment of Scotland.

The Highland Light Infantry (HLI) was a light infantry regiment of the British Army formed in 1881. It took part in the First and Second World Wars, until it was amalgamated with the Royal Scots Fusiliers in 1959 to form the Royal Highland Fusiliers (Princess Margaret's Own Glasgow and Ayrshire Regiment) which later merged with the Royal Scots Borderers, the Black Watch (Royal Highland Regiment), the Highlanders (Seaforth, Gordons and Camerons) and the Argyll and Sutherland Highlanders to form the Royal Regiment of Scotland, becoming the 2nd Battalion of the new regiment.

The Royal Highland Fusiliers, 2nd Battalion, Royal Regiment of Scotland (2 SCOTS) is an infantry battalion of the Royal Regiment of Scotland.

Prior to 28 March 2006, the Royal Highland Fusiliers was an infantry regiment in its own right, created by the amalgamation of the Royal Scots Fusiliers with the Highland Light Infantry (City of Glasgow Regiment) in January 1959.

The King's Own Scottish Borderers (KOSBs) was a line infantry regiment of the British Army, part of the Scottish Division. On 28 March 2006 the regiment was amalgamated with the Royal Scots, the Royal Highland Fusiliers (Princess Margaret's Own Glasgow and Ayrshire Regiment), the Black Watch (Royal Highland Regiment), the Highlanders (Seaforth, Gordons and Camerons), the Argyll and Sutherland Highlanders (Princess Louise's), 52nd Lowland Regiment, and 51st Highland Regiment to form the Royal Regiment of Scotland. However, after just a few months the battalion merged with the Royal Scots Battalion to form the Royal Scots Borderers.

The Black Watch, 3rd Battalion, Royal Regiment of Scotland (3 SCOTS) is an infantry battalion of the Royal Regiment of Scotland. The regiment was created as part of the Childers Reforms in 1881, when the 42nd (Royal Highland) Regiment of Foot (The Black Watch) was amalgamated with the 73rd (Perthshire) Regiment of Foot. It was known as The Black Watch (Royal Highlanders) from 1881 to 1931 and The Black Watch (Royal Highland Regiment) from 1931 to 2006. Part of the Scottish Division for administrative purposes from 1967, it was the senior Highland regiment. It has been part of the Scottish, Welsh and Irish Division for administrative purposes since 2017.

The Argyll and Sutherland Highlanders (Princess Louise's) is a light infantry company (designated as Balaklava Company, 5th Battalion, Royal Regiment of Scotland) and was a line infantry regiment of the British Army that existed from 1881 until amalgamation into the Royal Regiment of Scotland on 28 March 2006.

The regiment was created under the Childers Reforms in 1881, as the Princess Louise's (Sutherland and Argyll Highlanders), by the amalgamation of the 91st (Argyllshire Highlanders) Regiment of Foot and 93rd (Sutherland Highlanders) Regiment of Foot, amended the following year to reverse the order of the "Argyll" and "Sutherland" sub-titles. The Argyll and Sutherland Highlanders was expanded to fifteen battalions during the First World War (1914–1918) and nine during the Second World War (1939–1945). The 1st Battalion served in the 1st Commonwealth Division in the Korean War and gained a high public profile for its role in Aden during 1967.