War of the Frontiers

War of the Frontiers
Cacertian infantry attack at the Battle of Adrano
Date 16 March 1885 - 24 September 1885 Location Auroa Knichus Result Acrean Victory
Belligerents
Acrea	Cacertian Empire
Commanders and leaders
Ludvig Vikander Matthias Corriveau August von Braun	Zabina Padula Ariele Adinolfi Doriano Aliberti
Strength
Start of War 110,000 By September 1885 300,000	Start of War 305,000 By September 1885 450,000

The War of the Frontiers was an armed conflict fought between the Kingdom of Acrea and the Cacertian Empire from 16 March 1885 to 24 September 1885. The war was primarily caused by the desire of Elliana I to reduce or eliminate the Acrean sphere of influence in eastern Siduri and the Bara Sea. The conflict resulted in a swift Acrean victory which halted further Cacertian expansion into southeastern Siduri. Elliana I sued for peace and petitioned the Acreans for negotiations, which Acrean Queen Emma II acceded to, eventually culminating in the Treaty of Apridine which would dictate Acrean-Cacertian relations for over 70 years.

The Cacertian Army invaded the Acrean colony of Auroa in March 1885 with the goal of carving a land route into central Siduri from Knichus. Issues with their sealift capability left the Acrean forces in Siduri outnumbered over three to one despite advanced warning of the Cacertian troop buildup, forcing the Acrean territorial army to adopt unconventional asymmetric tactics. Although initially heavily outnumbered, the Cacertian invasion was halted and routed by a combination of new weaponry, such as the machine gun, and difficult terrain which favoured the defenders and supported asymmetric tactics employed by the Acreans. The tide was fully reversed after Acrean transport issues were resolved and large numbers of troops began to pour into Auroa, leading to a retaliatory invasion of Knichus and a return to conventional tactics in the second phase of the war. Although the invasion was successfully halted, Acrean troops effectively entrenched themselves in where they were stopped and were able to hold the ground they had gained. Several more months of stalemated fighting with relatively high costs forced Elliana I to sue for peace.

Acrea and Cacerta alike drew important lessons from the war that shaped their foreign and military policy going forward. For the Cacertians, the Acrean victory demonstrated how the Cacertian general staff had made miscalculations in the relative capabilities of Cacertian and Acrean forces that turned out to be critical, despite their assessments being otherwise largely correct. For the Acreans, the Cacertian invasion outlined dangerous complacency which had set in within Rena in regards to potential overseas rivals, and how unprepared the Acrean fleet had been to enable them to rapidly confront an adversary in Acrea's overseas territories. The war was the debut of both smokeless powder weaponry and the machine gun on the battlefield, and the devastating effectiveness of both stood out to both belligerents as well as foreign observers. In the war's aftermath, it served as a catalyst for a major rearmament and arms development program in Acrea, and a massive push for industrialisation and modernisation in Cacerta. In addition, it also convinced Elliana of the importance of growing the Cacertian fleet to compete head-to-head with the likes of foreign powers, and within several years a major naval development and procurement program was underway.

Background

Planning for a war with Acrea in Vichenza began in late 1883, a few months before the completion of the conquest of Liriniya in the the spring of 1884. Strategically, Acrea posed several challenges to Elliana I's ambitions for Cacertian expansion. The Acrean colony of Auroa and protectorate of Pteleia created a bulwark against any Cacertian expansion westward on the continent from Knichus, while Acrea's alliance with the Phạm dynasty gave it effective control over most of the eastern seaboard of Siduri. Importantly, Acrea also controlled the eastern mouth of the Sundering Sea; consequently, the Cacertians were effectively blockaded from reaching central Siduri without first dealing with Acrea. Initially, Elliana's government first considered negotiating with the Acreans to ensure open passage through the Sundering. Although considered the easiest and most expedient route, given the neutral relationship between Acrea and the young Cacertian Empire, concerns were quickly raised about how easily the Acreans could cut off this access if relations soured or a war broke out. Elliana's plans for expansion anticipated friction with Acrea, if not outright conflict at some point. Ultimately, Elliana and her general staff decided on pursuing a land route into Siduri through Auroa.

Beginning in mid-1884, Cacertian troops began arriving in Knichus via Liriniya, using the short sea routes which connected them to Cacerta. A force of some 300,000 was anticipated to be more than enough to overwhelm the Acrean territorial army in Auroa which was correctly estimated at no more than 50,000 troops. Holding much greater confidence in her army after the Liriniya campaign, at Elliana's insistence the plan was to restrict the conflict to a land-based one. She held skepticism in the ability of the Cacertian Royal Navy to successfully engage the larger Acrean fleet in a direct confrontation. With similar concerns held by her commanders, they decided to constrain the movement of the Cacertian fleet to instead protect the sea routes between Cacerta, Liriniya, and Knichus. Although the Cacertians took steps to conceal their troop movements, word eventually reached Rena of the developments via spies by late 1884, prompting the Acreans to begin deploying an army under Ludvig Vikander to Auroa to support the territorial army under August von Braun. Capacity issues plagued the Acreans, and the demands of trying to deploy a field army so quickly strained their largely untested sealift capability. Nonetheless, By the time the Cacertian invasion began in March, an additional 50,000 men had been deployed to Auroa from Acrea.

Course of the War

Auroan Campaign

The Cacertian operation began on 16 March, with a three-pronged advance into Auroa with its invasion force divided into three armies. The Cacertians initially met only moderate resistance, engaging with Acrean advance forces in skirmishes, though nonetheless pushed on. Although substantially outnumbered, the Acrean Army held a few key advantages over the Cacertians, though none more important than its weaponry. Compared to the Cacertians, Acrean forces held two technological advantages: smokeless powder weapons, and the machine gun. The advent of hvittpulver, a smokeless powder propellant, by Acrean chemist Stig Vignes in 1879 led to a rush by the Acrean military establishment to field weapons utilising this new technology in the years immediately after leading to the adoption of the Dessauer M1881. This development coincided with the gradual introduction of the MG m/78 into Acrean service. The first machine gun used by Acrea, the m/78 used black powder ammunition and was intended to replace a variety of rotary guns in Acrean service at the time. Smokeless powder ammunition solved numerous reliability issues related to the older black powder ammunition, and in 1883 the more developed MG m/83 was introduced using the new ammunition. Cacertian forces, used to expeditionary warfare, were fairly lightly equipped with only light artillery and some rotary guns. Acrean forces at the start of the conflict were similarly equipped with only light howitzers and their machine guns, though as more forces arrived from Acrea they brought with them heavier howitzers.

Cacertian and Acrean troops first met in a major battle at the strategic town of Aonotena approximately a week after the start of the invasion. Located along a major travel route, Cacertian commander Doriano Aliberti sought to capture the town to secure a location to set up a forward depot, for which it was ideal. Expecting moderate resistance, Aliberti's attack was almost immediately halted when it encountered entrenched Acrean positions along the eastern perimeter of the town. The unrelenting fusillade of machine gun fire inflicted heavy casualties on the initial assault force.

Aliberti divided his forces to assault the Acrean flanks while continuing to draw fire to the front. Having witnessed the first waves of troops cut down by the guns and accurate Acrean rifle fire and recognising they were outmatched in firepower and outranged, his officers divided their forces into smaller elements and made the most of what cover and concealment was present to close the distance to the Acrean positions. The grassy, open, flat terrain of southeastern Auroa made this task difficult however, and the Cacertians only experienced success along the Acrean southern flank where orchards provided enough cover to reach and seize a foothold on the outskirts of the Aonotena. Aliberti moved to reinforce this position, but reinforcements arrived too late as the Cacertians had once again been pushed back after a counter assault and hand-to-hand fighting by the defenders. The Acreans sought to extend their southern perimeter and tried to seize the orchard, but were pushed back into their previous positions by the numerically superior Cacertians. The positions would change hands several more times throughout the day, only finally being held by the Acreans after they managed to reposition a machine gun, the incessant fire of which ripped through the orchard and made any further attacks untenable. After a day of hard fighting and horrific casualties, Aliberti withdrew back east.

The results of the battle were repeated when the other two Cacertian field armies, led by Zabina Padula and Ariele Adinolfi, encountered similar Acrean defensive positions. The entrenchments made the positions difficult to counter with their light artillery, while the sustained fire of the machine guns made any frontal assault suicidal. Open terrain and scarce large foliage in eastern Auroa favoured the Acreans, who use more mobile light troops in conjunction with their static positions to counter Cacertian tactics. Cacertian commanders quickly adapted to the underestimated power of Acrean heavy weapons, and opted to bypass Acrean defensive positions around settlements and strategic positions entirely, taking advantage of the lack of mobility and need for entrenchement for the machine guns. Though they recognised that this option was risky by leaving their logistical trains open to attack from Acrean garrisons, it was decided that assigning more troops to rear security was desirable over the heavy casualties suffered when attacking such positions.

Though their new strategy enjoyed initial success, the Cacertians quickly became mired down in the terrain by a combination of Acrean regular light infantry and native Auroan militia. The latter were noted after the fact as being particularly effective when their intimate knowledge of the terrain was combined with new Acrean rifles, with Adinolfi commenting after the conflict that they likely inflicted even much damage on the Cacertian armies than the machine guns. The Acreans were only able to effectively outmaneuver and defeat the Cacertians in a major engagement with the arrival of reinforcements from Vikander's army after inflicting several weeks worth of attrition, eventually routing the beleaguered Cacertians at the Battle of Teaorongo in late April and then forcing them into retreat a couple of weeks later at Katarorae.

The war entered a brief lull from late may to June. Weary and having suffered severe casualties, the Cacertian armies withdrew to the border while being harassed by Auroan militia to rest and refit, while fresh Acrean troops continued to pour in from the port at New Alexandria. Though reinforcements were arriving in theater from Cacerta, the Cacertans lacked the substantial rail infrastructure in Knichus that the Acreans enjoyed in Auroa. Additionally, many regiments were not in adequate fighting shape, resulting in a number being combined while some were rotated out of country to be replaced by newly arrived troops. As a result, Cacertian numbers only gradually increased while Acrean troop numbers swelled by the week.