By 1691, the Jacobites had adopted a defensive position. In the previous year they had retreated into
Connacht behind the easily defensible line of the
Shannon, with strongholds at
Sligo,
Athlone and
Limerick guarding the routes into the province and the western ports. William
besieged Limerick in late August 1690 but, suffering heavy casualties and losses to disease, he called off the siege and put his army into winter quarters. However, internal divisions, exacerbated by the departure of James for France after defeat at
the Boyne, were increasingly undermining the Jacobite command. The main split was between the "Peace Party", led by James's viceroy
Tyrconnell, which proposed negotiating a settlement with William, and the "War Party" of army officers grouped around
Patrick Sarsfield, who believed the war could still be won outright. Encouraged by William's failure to take Limerick and looking to break Tyrconnell's influence, Sarsfield's faction decided to appeal directly to
Louis XIV of France requesting that Tyrconnell and army commander
Berwick be removed from office and that Louis send military aid. The "Peace Party" obtained an offer of settlement from the Williamites in December, upon which Sarsfield demanded that Berwick have
Riverston,
Denis Daly and other "Peace Party" leaders arrested. Berwick complied, probably with the approval of Tyrconnell, who returned from France to try and preserve his influence by repositioning himself with Sarsfield's faction. Louis sent general
Charles Chalmot de Saint-Ruhe to replace Berwick as senior Jacobite commander, with secret instructions to assess whether Louis should send further military aid. By this stage William's forces were led by his subordinates, Dutch officer
Godert de Ginkel and second-in-command
Württemberg. Ginkel was conscious of the poor military situation facing William in the Netherlands, and seeking a quick end to the war obtained William's permission to offer the Jacobites moderate terms of surrender. By late spring 1691, however, Ginkel became concerned that a French convoy could land further reinforcements at Galway or Limerick, and began planning to enter the field as quickly as possible. During May, both sides began assembling forces for a summer campaign, the Jacobites at Limerick and the Williamites at
Mullingar. On 16 June, Ginkel's cavalry reconnoitred from
Ballymore towards the Jacobite garrison at Athlone. Saint-Ruhe had been unsure where Ginkel would attempt to cross the Shannon, but by 19 June he realised Athlone was the target and began concentrating his troops west of the town. Ginkel breached the Jacobite lines of defence and took Athlone on 30 June after a
bloody siege; Saint-Ruhe was unable to relieve the town and fell back to the west. Athlone was seen as a significant victory and likely to provoke the collapse of the Jacobite army. Unaware of the location of Saint-Ruhe's main army and assuming he was outnumbered, on 10 July Ginkel continued a cautious advance through
Ballinasloe down the main Limerick and
Galway road. Saint-Ruhe's and Tyrconnell's plan had been to fall back on Limerick and force the Williamites into another year of campaigning, but wishing to redeem his errors at Athlone Saint-Ruhe appears to have instead decided to force a decisive battle. Ginkel found his way blocked by Saint-Ruhe's army at
Aughrim on the early morning of 12 July 1691.
Deployments At this point of the campaign, both armies were about 20,000 strong. The core of the Jacobite force was formed around James's old
Irish Army, which had been reorganised by Tyrconnell from 1686 onwards by dismissing the majority of Protestant officers and men. It had been substantially expanded with newly recruited Irish Catholic regiments, organised in the English military tradition. While it is not now possible to establish with certainty which Jacobite infantry regiments fought at Aughrim, at least 30 have been identified as likely present, including the
Foot Guards,
Talbot's, Nugent's, Fitzgerald's,
Boffin's, Cormack O'Neill's, Saxby's and Iveagh's. The Jacobites also retained around 4,000 cavalry and
dragoons, mostly much better trained and equipped than their foot. The composition of Ginkel's army is better documented than that of the Jacobites: in addition to English regiments, it included a large number of
Anglo-Irish Protestants as well as Dutch, Danish and French
Huguenot contingents. Different contemporary sources give different dispositions for Ginkel's forces at Aughrim, but most agree that the right wing was composed of English, Anglo-Irish and Huguenot cavalry, with Danish and French cavalry on the left. Ginkel positioned the English infantry regiments on the right of his centre, with French, Danish and Dutch foot on their left. To protect his largely inexperienced infantry, Saint-Ruhe deployed most of it in two divisions under Major-Generals
John Hamilton and
William Dorrington along the crest of a ridge known as Kilcommadan Hill, their positions protected by small hillside enclosures and hedgerows. The centre was further screened by a large bog, impassable to cavalry, through which the Melehan River flowed. The left flank was also bounded by "a large Red Bogg, almost a mile over", According to one participant's account
Patrick Sarsfield had quarrelled with Saint-Ruhe and was posted with the cavalry reserve to the left rear, under strict instructions not to move without orders. ==Battle==