In 1882, under the direction of Belgian military architect Henri Alexis Brialmont, he supervised the building of a Romanian system of defensive fortifications on the line Galați–Nămoloasa–Iași, and around the capital Bucharest.

That same day, 80,000 soldiers of Culcer's Romanian 5th Corps crossed the border into Southern Dobruja and occupied the line from Tutrakan to Balchik.

The cavalry attached to this corps briefly occupied the Black Sea port of Varna, but retreated back into Dobruja when the lack of Bulgarian resistance became apparent.

[9] For his efforts, King Carol I appointed Culcer Governor of Southern Dobruja, the province annexed by Romania after the 1913 Treaty of Bucharest.

Romania's latest proper combat foray consisted in its involvement in the 1877 – 1878 Russo-Turkish War, fighting closer in technology and spirit to Waterloo than to Somme or Verdun.

[11] Culcer thus had as much combat experience as a full-time Romanian commander could have, having served as an officer in both of these wars: as a First Lieutenant in the 1877 – 1878 campaign,[2] and as a General in the 1913 invasion of Bulgaria.

Following an entire day of fighting, the Romanians defeated the 51st Honvéd Division and the 143rd Brigade, causing the Austro-Hungarian defenders to retreat to the heights on both sides of Sibiu.

General Matei Castriș – commander of the Olt-Lotru Group and later of the 23rd Division – ordered his columns to halt, establishing three lines of trenches running from Veștem to the Red Tower Pass.

Sixty-five miles to the west, the 11th Division (Brigadier-General Ioan Muică [ro]) crossed the border at the Vulcan and Surduc Passes and occupied the vital Transylvanian coal-mining center at Petroșani – a local district capital – on 29 August.

This was the first location of any military or commercial value to fall into Romanian hands, a region of valuable coal mines whose output was vital for the Hungarian railway system.

Some of the Romanian generals – Culcer included – understood that waiting for their forces to regroup would waste the opportunity to advance against an enemy which – at the time – was weak, confused and disorganized.

Several days into the campaign, Culcer decided to make the Olt Group a de facto corps headquarters, with General Constantin Manolescu [ro] in command.

[33] Further west, by 3 September, the 1st Army occupied the important coal area between Uricani and Petroșani, driving back the ineffective Landsturm and miners battalions of the 144th Infantry Brigade over the saddle of Merișor.

[17] On 8 September, the XXXIX Reserve Corps of German General Hermann von Staabs assumed responsibility for operations in southern Transylvania.

[53] Culcer ordered the deployment of an infantry company to the region north of Voineasa, in the wild and mountainous area which separates the Olt and Jiu Valleys.

Normally, keeping surveillance over such a large area with only one company of soldiers would be impossible, but the Romanians also disposed of border guards and customs officials scattered throughout the mountains, and most of these posts – housed in hunting lodges and cabins – had telephones for reporting activity.

Konrad Krafft von Dellmensingen's Alpine Corps Division was to act as an anvil, seizing the Red Tower Pass in order to block a Romanian retreat.

Hermann von Staabs's Corps, assembling northwest of Sibiu, was to act as a hammer, driving southeast towards the mouth of the Red Tower Pass at Tălmaciu.

Romanian frustration with having to endure this bombardment boiled over, and on 22 September General Popovici ordered his 13th Division to take the heights at Roșia, east of Sibiu.

The Romanian attack had driven a wedge between von Schmettow's two cavalry divisions, which — if exploited — could expose the flank of the 9th Army and ruin the plans to take Sibiu.

[58] Popovici's only real success was attained south of Cornățel, where the Romanians faced the extremely thinly-held positions of the 7th Cavalry Brigade of the 1st Division.

Just before arriving at the overnight bivouac, the Jäger brigade (General Ludwig Ritter von Tutschek) drove off some Romanian guards in a sharp fight.

On the 25th, von Tutschek's infantry continued east, splitting into two columns: one stopped at a forest lodge at Prezba and the other halted in meadows on either side of Varful Mare.

That same morning, the Alpine Corps occupied the Red Tower Pass at several points, including areas on the southern (Romanian) side of the border.

[67][68] During the 27th, German and Hungarian regiments slowly made their way through Daia, Bungard and Cașolț, also capturing the 601 meters-tall Grigori height (the northernmost Romanian position, northeast of Sibiu).

Other losses included 10 locomotives with 700 loaded railway wagons (300 of small arms ammunition, 200 of artillery munitions and 200 filled with baggage), 70 cars and trucks, a hospital train and a paymaster's supplies.

[76] In consequence, the Romanian troops which defeated the first Central Powers offensive south of the Red Tower Pass in late October were those beaten at Sibiu in September.

[80] On 19 September, after entering Petroșani on the 18th, the Germans took the Surduc Pass as the inexperienced General Muică – commander of the Romanian 11th Division – retreated back across the border.

Sympathetic ethnic-Romanians living in the region immediately made General Culcer's headquarters aware that the bulk of the Germans had pulled out of the area.

[89] Certain sources appear to be surprised by the Romanian success, that – after being overwhelmed by the artillery used against his forces during what was at the time General Falkenhayn's main blow – Culcer was "even able" to make some headway against his opponents.