Despite the rising international tensions following the assassination of Archduke Franz Ferdinand on 28 June, the High Seas Fleet began its summer cruise to Norway on 13 July. During the last peacetime cruise of the Imperial Navy, the fleet conducted drills off Skagen before proceeding to the Norwegian fjords on 25 July. The following day the fleet began to steam back to Germany, as a result of Austria-Hungary's ultimatum to Serbia. On the 27th, the entire fleet assembled off Cape Skudenes before returning to port, where the ships remained at a heightened state of readiness. War between Austria-Hungary and Serbia broke out the following day, and in the span of a week all of the major European powers had joined the conflict.