SMS Cormoran was originally a passenger and cargo ship, named SS Ryaezan and built by the Germans in 1909 for the Russian merchant fleet.

Setting out from Qingdao on August 10, 1914 for a commerce raiding cruise in the South Pacific, SMS Cormoran failed to sink any enemy shipping as she spent all of her time avoiding allied warships.

Captain Zuckschwerdt pulled into Apra Harbor, Guam on December 14 with the intention of receiving coal from the Americans on the island.

In case anything went wrong, the artillery battery of three 7 inch guns on the western face of Mount Tenjo was also trained on the vessel.

A similar incident occurred in 1915 at Fort San Felipe del Morro in the Caribbean, America's very first shot was fired, at a different German auxiliary cruiser which was also interned in a neutral American port.