It is not clear what happened to him on that day and despite almost 1900 years of speculation, historians have been unable to agree on the events which took place on that fateful day.
What is known is that Hadrian spent three days searching for his beloved Antinous.
On the third day, Antinous' body was recovered from the Nile. His legs and feet were covered in red lotus flowers. The red lotus has since become a symbol of Antinous.
Ever since that day the world has not stopped to speculate as to how the beautiful, athletic twenty year old lover of the most powerful man in the world could simply drown in a river which had failed to flood for two seasons in a row.
Was it a simple accident, suicide or something more sinister ?
It is difficult to believe that Antinous' death could have been an accident. The river was not dangerous at the time and Antinous was by all accounts a keen sportman.
Was it murder? There is evidence that the relationship between the Emperor and Antinous had attracted powerful enemies, including the Empress as well as the two main contenders in line to succeed Hadrian as Emperor. It is entirely possible that a sinister plot to finally rid the Court of the Emperor's lover was responsible for Antinous' death.
Could it have been suicide?
To the Egyptians at the time, this was the most likely cause of death. However, it wasn't considered to be suicide in the usual sense of the word...
According to the Greek religion in which Antinous had been raised, if a person sacrificed his life for his lover, that lover would receive the additional life span of the person who had sacrificed himself.
Given Hadrian's ill health and the clear devotion to him which Antinous had, it is possible that through his death, Antinous attempted to increase Hadrian's life span.
This possibility becomes even more likely in light of a startling and disturbing prophesy which was given to Hadrian and Antinous by a priest, as they arrived in Egpty:
Antinous would be the cause of the Emperor's downfall.
It is possible that Antinous sacrificed his life to save his lover.
Ironically, it was Antinous' death, the circumstances surrounding it and Hadrian's insane grief which eventually caused the people and the Senate of Rome to turn against him.
Whatever the reason for Antinous' death, Hadrian was heartbroken.
some assert that he sacrificed himself for Hadrian, others what both his beauty and Hadrian's excessive sensuality make obvious."
Historia Augusta
'Antinous Osiris was a youth whose beauty delighted the eyes and whose heart was wise; his intelligence was that of a grown man. He was beloved in the hearts of his attendants...His praises to intelligent beings making him take his place in the temples of his followers and wise spirits who are by the power of Osiris in the land of Hades devine forever.'
The Nile flooded. Egypt was saved. A new star appeared in the heavens.
To the Egyptians these were sure signs that through his death and subsequent resurrection as a star, Antinous had become a god, an aspect of Osiris who himself had died and disappeared in the Nile, had been mourned and searched for by his wife Isis and had finally been resurrected to eternal life.