Garrison Regiment I was raised in 1718 as a single battalion. In 1744 it was increased to 2 battalions. In 1756 it was again increased, to 4 battalions. The regiment's recruits came from East Prussia, namely the cities of Memel, Wehlau, Tapiau, Hohenstein, Nordenburg, Schirwindt and Stallupönen. In 1756 it was the garrison of Königsberg, Gumbinnen, Memel and Pillau, plus Stettin in 1760.
In the winter of 1757-8 the 2 battalions of the regiment in garrison in Königsberg and Pillau withdrew into Pomerania on hearing the news that the Russian general Fermor intended to retake East Prussia. "They took with them the money, the greater part of the stores and the artillery" (Kronoskaf). At the end of June 1758 the regiment stayed in Pomerania to face the Swedes, Dohna's small Prussian army having left Pomerania to confront the Russians in Brandenburg. In 1759 the regiment was defending the mouth of the river Oder against the Swedes but withdrew in September. In mid-September 1 battalion of the regiment and Land Militia Battalion No.4 Wasmer were defending the town of Wollin; on the 16th the Swedes stormed the town, capturing the garrison. (Details from Kronoskaf.)
The grenadiers of the regiment were combined with the grenadiers of Garrison Regiment XI during the war up to 1760, forming Standing Grenadier Battalion Nr. IV (G-I/G-XI Lossau). From 1760 they were combined with the grenadiers of Garrison Regiment No.II to form the same standing grenadier battalion. They fought at Gross-Jägersdorf in 1757, Zorndorf in 1758 (around 40% casualties - Duffy, Army of Frederick the Great, 1st edition), Kay and Kunersdorf in 1759 and Torgau in 1760.
This is the most elaborate style of garrison regiment flag, carried only by regiments 1 and 2. It is very similar to the flags carried by many of the regular line infantry regiments, except for the wreaths which are in the style carried by the other garrison regiments and which are very similar to the design of wreath used on the flags of the regiments of Frederick William I, Frederick's father. The regimental flag design is shown at the top (Kompaniefahnen), the Colonel's flag (or Leibfahne) at the bottom.
