[3] While outwardly a period of peace and prosperity, opposition against Charles was growing, in part over his use of medieval laws to raise money and his use of the prerogative courts of the Star Chamber and High Commission.

[2][3] Charles also attempted to enforce consistent religious practices across his realm, prosecuting both those who supported a return to the Roman Catholic Church, and puritans who sought the end of episcopacy.

This favouritism came at the expense of Calvinism which had been widely practised under James, with opponents of Charles and Laud equating their policies with Catholicism, to which Calvinists were strongly opposed.

[8] From his accession in March 1625 Charles was the first permanently absent ruler of Scotland, relying on Scots resident in England, from where he ruled both kingdoms, to advise him.

James had sought to rein in the independently minded Kirk and bring Scottish religious practices inline with those in England, including the reintroduction of bishops and taking control of the general assembly.

[4] Charles had continued these policies over the objections of the Presbyterian Kirk and during his brief visit in 1633 for his coronation as king of Scotland the elaborate and ritualistic ceremony led by Archbishop Laud had offended Scottish tastes.

In 1637, a modified version of the prayer book similar to those used by the Church of England was forced upon the Kirk, previously without any consistently defined form of worship, leading to riots starting in St Giles', Edinburgh.

[9] Time and distance prevented Charles from responding effectively as the situation escalated with Scottish nobles lining up behind their ministers to reject these ecclesiastical reforms and taking advantage of Scotland's looser legal system to mount a direct challenge to the king's rule.

[11] A National Covenant was drawn up in January 1638 which while moderately worded was an attack on Charles' Personal Rule and sought to justify a revolt against the sovereign,[10] including a demand for assemblies and parliaments free of royal interference.

These were to be aided by Randal MacDonnell, 1st Marquess of Antrim, who was to raise his followers in Ireland and Scotland with the aim of gaining control of the western Highlands and islands.

Hamilton was eager to create an alliance against Clan Campbell, and suggested to Charles in May 1638 that an army raised and paid for by Antrim should be the first line of offence in western Scotland.

[18] In 1639 England had no standing army and the force Charles ordered to muster consisted of the militia of the northern counties, alongside a special levy of 6,000 volunteers and additional horse troops raised through invoking half-forgotten feudal obligations of the king's tenants-in-chief.

[19] Jacob Astley, a veteran of wars in Europe, was appointed to lead the infantry and upon arrival at the muster at York was shocked by the state of the militiamen and their inadequate weapons.

[13] Sufficient numbers of veterans recalled to Scotland would return to train the army in time for the campaign of 1639, and Leslie was also able to advise on the procurement of arms from the continent.

[24] Leslie would be granted a commission as general of all Scottish forces on 9 May 1639, deliberately chosen as someone who stood outside the tensions which could have caused rivalry and feuding which may have undermined the Covenanters' efforts.

[25] On 30 March a covenanter army under the command of James Graham, Earl of Montrose, and Alexander Leslie entered the Royalist burgh of Aberdeen and captured Huntly.

[16] Huntly's second son, the Viscount Aboyne, took command of the Royalists in north-east Scotland following his father's capture, and entered Aberdeen on 6 June but apparently lacked a clear plan.

[28] Faced with low resources and the Covenanters in control of the strong points which had historically slowed down invasions from England, Charles' generals advised against becoming bogged down in a long campaign.

The 1639 General Assembly held in Edinburgh ratified the abolition of episcopacy and the Covenanters prepared a radical political and constitutional agenda for the parliament which met on 31 August.

In Scotland, it forced the earl of Argyll into the Covenanting camp along with his supporters, while in England it showed Charles was willing to conspire with an Irish papist against his protestant subjects, helping fuel rumours of popish plots circulating around London.