Early service

In 1739, Rosenberg was born into a family belonging to the Baltic nobility. He joined the Imperial Russian army and fought against the Kingdom of Prussia in the Seven Years' War and Ottoman Turkey in the Russo-Turkish War of 1768–74, including participation in the naval battle of Chesma, the ravaging of that city, and the capture of its artillery batteries. He also led troops against the Poles during the War of the Bar Confederation in 1778–9.^[1][5]

Italy and Switzerland

Suvorov's Swiss campaign; Rosenberg's column is a solid thin line

In 1798 Rosenberg was assigned to lead the first echelon of the Russian army sent to assist Habsburg Austria in Italy during the War of the Second Coalition. During his corps' passage across Habsburg territory, Rosenberg kept strict discipline among his soldiers while ensuring that his hosts kept up their end of the bargain with regard to providing his men with food and living quarters. Rosenberg was remembered as being highly professional and concerned with the welfare of his men, but aloof in his dealings with the rank and file. In his first meeting with the new army commander he did not make a good impression on Alexander Suvorov. Nevertheless, he was reassigned to lead the second echelon when Wilhelm Derfelden assumed command of Rosenberg's original corps.^[5]

Suvorov learnt that the Archduke Charles, who was with Rimsky-Korsakov in Switzerland, came out of Switzerland, leaving Korsakov alone against Masséna's French army. This news is very concerned Suvorov for the fate of Rimsky-Korsakov's detachment and forced to hurry toward Switzerland, to the upper Reuss, he intended to go to the rear of Masséna's army, about which he notified Rimsky-Korsakov. Rosenberg's troops marched in an advanced column, opening the way for the rest of the troops. Steep ascents and descents slowed down the movement; and, it was pouring rain. The troops made their first overnight stay, from 22 to 23 September, on a snowy ridge, in a cold stormy night, at an altitude of 8,000 feet, without kindling to build bivouac fires; the packs all fell behind. At dawn on the 23rd Rosenberg first climbed the steep ascent to the snowy ridge, then descended into the gorge of the Reuss, and along it reached Disentis, where he saw a spacious valley; the troops, continuing on their way, arrived at the lodging by midnight, having travelled in three days about 80 km; there were almost no stragglers: those who were exhausted were supported by their comrades. On the 24th of September Rosenberg had to go to the Urseren or Andermatt and on the way to attack the French, who stood in the Urner Loch position under the command of Gudin. The position from Italy's side was unavailable: there was a narrow path leading to it, barely suitable for packs, on a steep, winding slope, crossed more than once by mountain streams. Having taken a detour, Rosenberg began to appear in the French rear and thereby induced them to leave the position occupied by him, on which Suvorov also led the attack. Fog and night darkness favoured the French retreat. Rosenberg, not knowing the terrain, stopped in the Urseren, where he arrived at 7 o'clock in the evening. At dawn on 25 September went on to the Devil's Bridge, also occupied by the French. It was necessary to descend into the Reuss River's gorge, to cross the turbulent stream, waist-deep in water, then to climb up to the left bank's mountain heights and to appear in the French rear. After a long battle the troops reached Altorf, where Lecourbe held a position. Rosenberg's troops lined up in battle order, soon knocked out the French and occupied Altorf on the 26th of September, where they found a lot of supplies of all kinds, which were very useful for them.^[1]

Later years

When Suvorov's Swiss campaign was over, Rosenberg was awarded the Order of St. Andrew the First-Called on 9 November 1799. Soon there was a spat between Emperor Paul I with his ally,—and he ordered Suvorov to return with his army to the fatherland. The army went on a return march, in Kraków; in March 1800, Field Marshal Suvorov said goodbye to it and handed over command of it to the senior man after him — Rosenberg, who brought the army to its homeland. Emperor Paul appointed Rosenberg (20 June 1800) military governor of Kamenets-Podolsky, troop inspector of the Dnieper Inspection and chief of the Vladimir Musketeer Regiment. In 1803, on 23 October, Alexander I entrusted him with the Kherson Governorate management, appointing him military governor of Kherson and inspector of the Crimean Infantry, — but not for long: in 1805, Rosenberg asked for dismissal from service due to ill health and on 25 March was dismissed with retention of all the salaries he was receiving. He died on 7 September 1813 in the old town of Chyornoye, 32 km from Kamenets-Podolsky, granted to him by the Emperor Paul for 50 years. Rosenberg was not married.^[1]