There is confusion because the contemporary sources disagree on exactly how the Holy Roman Emperor met his death, in a river in southern Anatolia, on his way to fight in the Third Crusade.

There are four key sources and they tell different stories. The most detailed, Ansbert's Expeditio Friderici, recounts:

"He tried to swim the channel of the Saleph river [the same river as your Göksu], a very rapid one... In spite of everyone's attempt to dissuade him, he entered the water and, submerged in a whirlpool, he who had often avoided great dangers miserably perished."

Also of interest is "A letter concerning the death of the Emperor Frederick," written in newsletter form at the time of the incident, and certainly completed before the expedition arrived at Antioch, which states:

The lord emperor had crossed these valleys and mountains through a short cut, and on this same day [Sunday, 10 June 1190] he traversed this fast-flowing river and reached the other side in safety. He had lunch there, and, after the many and terrible exertions that he had undergone in the previous month and more, he decided to bathe in that same river, for he wanted to cool down with a swim. But by the secret judgement of God there was an unexpected and lamentable accident and he drowned."

The Chronicle of Otto of St Blasien, which also states that Frederick entered the river "in the hope of cooling down", and adds that he was a good swimmer, offers: "The sudden cold extinguished his natural heat and he was drowned." Otto adds that the body was divided into two portions: "His intestines and the rest of his flesh were buried at Tarsus, while his bones were brought to Antioch." This would suggest that the flesh, which would have rotted very quickly in the summer heat, had to be disposed of quickly - Tarsus is the closest major city to the death-spot - while the remains that could better be preserved were carried on to the holier city, Antioch.

Christopher Tyerman summarises the divergent accounts as follows:

As the German army negotiated the crossing of the River Saleph, Frederick somehow slipped, fell or was thrown from his horse into the river. He may have fallen in because of a heart attack, or, having fallen, the shock of the cold water brought one on. Alternatively, and less credibly, he drowned after going for a cooling swim. The sources disagree, some insisting that Frederick survived his ducking only to die some days later."

Worth noting is Frederick's age at the time of his death - 70, extremely advanced for the period. He was certainly old enough for physical infirmity of some kind to have played its part.

Regarding the recovery of Frederick's body: Runciman (who I appreciate is not widely read these days) recounts the same confusion, but adds: "By the time that the army reached the river his corpse had been rescued and was lying on the bank." Wolff and Hazard add the detail that "Other nobles near him hastened to help him... they were too late ... They then took him out and brought him to the bank." There doesn't seem to be anything else in the sources about the recovery of the body, but clearly the river was shallow enough to ford around the place where Frederick died, so this need not be considered a puzzle.

Sources

G.A. Loud, The Crusade of Frederick Barbarossa: The History of the Expedition of the Emperor Frederick and Related Texts pp.8-9, 172, 180.

Stephen Runciman, A History of the Crusades 3: The Kingdom of Acre p.15.

Robert Lee Wolff and Harry M Hazard, The Later Crusades 1189-1311 p.11

Christopher Tyerman, God's War: A New History of the Crusades p.427.