He ascended to the Oldenburg throne in 1900 as Frederick Augustus II and funded multiple infrastructure projects, including the development of ports and waterways.

The First World War broke out during his reign which saw the Grand Duchy of Oldenburg fight with the German Empire under Kaiser Wilhelm II on the side of the Central Powers.

[2] Frederick Augustus acquired a captain's licence at a nautical school in Elsfleth and began to regularly skipper yachts.

Considered conservative by the German media, Frederick Augustus was a supporter of Wilhelminism and became interested in the development of technology, seafaring and the navy.

He also invested in the development of waterways, including the Hunte Canal, which expanded Oldenburg ports on the Weser and promoted the construction of new industrial factories.

[2] German historian August Geerkens wrote of Frederick Augustus: "He was popular with the population; everyone smiled when his car drove through the streets with all the fanfare.

[8] Being a state of the German Empire, the Grand Duchy of Oldenburg took part in World War I, under Frederick Augustus' rule.

He personally commanded the Grand Ducal Oldenburg Cavalry Regiment during the war, in which he adhered to a group of annexationists, who wanted to secure Germany's position of power by acquiring foreign territories.

He supported the invasion of Belgium and believed that France should be made a vassal state of Germany and be divided into a northern republic and southern Bourbon Kingdom.

[9] According to Geerkens, Frederick Augustus was pushed by Grand Admiral Alfred von Tirpitz to approach the King of Bavaria, Ludwig III, and suggest that the German monarchs demand that Wilhelm dismiss the Chancellor of Germany, Theobald von Bethmann Hollweg, who was accused of acting too weak and slowing German victory.

[12] Philosopher Karl Jaspers, who grew up in Oldenburg, wrote in his memoirs of this endeavour: "The Grand Duke used some of the money from the sale of the pictures to help found a sausage factory, which subsequently collapsed.

Due to this increased status, the weddings were attended by many important personages, including Leopold II of Belgium and his wife, Queen Marie Henriette.