When open war broke out between the King and Parliament, neither side made much use of the trained bands beyond securing the county armouries for their own full-time troops.

Under the Commonwealth and Protectorate the militia received pay when called out, and operated alongside the New Model Army to control the country.

[5][24][25][26] The Pembroke Militia was called out in 1667 during the Second Dutch War when there was an invasion panic following the Raid on the Medway and the Battle of Landguard Fort.

On 11 August, when he inspected the Pembrokeshire Militia near Haverfordwest, it consisted of a regiment of foot ('all of firelocks', ie musketeers with no pikemen) and one Troop of horse.

An adjutant and drill sergeants were to be provided to each regiment from the Regular Army, and arms and accoutrements would be supplied when the county had secured 60 per cent of its quota of recruits.

[29][39][32][40][41] After a short period of training and organised into four small companies the regiment marched off in January 1760 to take up garrison duties at Bristol.

The militia were embodied, and the Pembrokeshires were called out on 26 March, assembling at Haverfordwest shortly afterwards under the command of Major Wyriot Owen.

His second-in-command was Capt John Colby, brother-in-law of the former colonel, now Sir Hugh Owen, 5th Baronet of Orielton and Lord Lieutenant of Pembrokeshire.

This was the army's largest training camp, where the Militia were exercised as part of a division alongside Regular troops while providing a reserve in case of French invasion of South East England.

The understrength militia units from small counties (Montgomery, Radnor and Pembroke) were attached to guard the artillery park of the division.

On 4 November the camp broke up and the Pembrokeshires marched into Maidstone for winter quarters, sending parties back to Haverfordwest to collect recruits.

By November detachments were billeted in villages north and east of London, but the regiment then marched off to winter quarters in Haverfordwest, arriving on 18 December.

The Gordon Riots broke out in London in June, and the Pembroke Militia was called out in aid of the civil power, with short deployments to Brentwood and Romford, without any clashes occurring.

[45] In spring 1782 the Pembrokeshires returned to Coxheath Camp, where it became part of a brigade including the Brecknockshire and Merionethshire Militia regiments and Sir John Leicester's Dragoons, all commanded by Lt-Col Colby.

The Pembrokeshire Militia under Lt-Col Colby had already been embodied at Haverfordwest on 2 January and later that month it marched via Worcester to Romford in Essex, where it was stationed until June.

[39][47][48] The French Revolutionary Wars saw a new phase for the English militia: they were embodied for a whole generation, and became regiments of full-time professional soldiers (though restricted to service in the British Isles), which the regular army increasingly saw as a prime source of recruits.

In common with other small Welsh militia units, the Pembrokeshires provided men to assist the gunners in the redoubts protecting the naval dockyard.

[29][39][32][40][55][56] The HQ remained at Colchester until the summer of 1806, when the detachments were called in and the regiment concentrated at Maldon before joining the Harwich garrison.

The following month the Royal Pembrokeshires (except one man) volunteered to be attached to the 43rd (Monmouthshire) Light Infantry for service with Sir John Moore in the Peninsular War in Spain.

Although officers continued to be commissioned into the militia and ballots were still occasionally held, the regiments were rarely assembled for training (only in 1818, 1821 and 1831) and the permanent staffs of sergeants and drummers were progressively reduced.

The Royal Monmouth Light Infantry (RMLI) were embodied in May and stationed at Pembroke Dock, where they volunteered for overseas garrison service.

The regiment was assembled for its first 28-day training at Haverfordwest on 12 June, but it was not until 30 January 1855 that it was embodied for permanent service, with 200 gunners enrolled, together with a small band of German musicians.

However, the commanding officer and surgeon of the RMLI at Pembroke Dock chartered a small steamer, and got close enough to throw some supplies onto the landing stage on the island.

[67] The Treaty of Paris signed on 30 March 1856 brought the war to an end, and in July the Royal Pembroke Artillery returned to Haverfordwest and was disembodied.

However, the Welsh militia artillery often carried out their annual training at the same time, so the batteries around the Haven could cooperate in live-firing exercises against target vessels, and with the searchlights and defensive mines operated by the Royal Engineers.

There were moves to reform the Auxiliary Forces (Militia, Yeomanry and Volunteers) to take their place in the six Army Corps proposed by St John Brodrick as Secretary of State for War.

[78][79] Under the sweeping Haldane Reforms of 1908, the Militia was replaced by the Special Reserve, a semi-professional force whose role was to provide reinforcement drafts for regular units serving overseas in wartime.

An officer's Epaulette of about 1811 carries as a badge the Prince of Wales's feathers, coronet and motto with a scroll beneath inscribed 'ROYAL PEMBROKE'.

About 1860 the badge on the officers' pouchbelt plate consisted of the Prince of Wales's feathers, coronet and motto inside a crowned garter inscribed 'ROYAL PEMBROKE'.

On khaki service dress the brass shoulder title read 'RGA' over 'PEMBROKE' and the cap badge was that of the RA with 'M' between the gun and the scroll.