It was erected in 292 AD, on the top of the platform of the temple of Serapis by the people of Alexandria as a thank giving for the Roman Emperor Diocletian.

There was a revolt at Alexandria and the Roman Emperor came and surrounded the city until it surrendered because of hunger and famine, when he entered the city, he distributed wheat and corn among the people of Alexandria for free in order to decrease the effect of the famine on the people, in return the people of Alexandria erected this pillar as a way to thank him.

This pillar was made out of red granite and consists of the base, the shaft and the capital. It measures about 26.85 m. in height; while its diameter at the tower end was 23 m. in other words it is tapering towards the top.

The capital of the pillar was of Corinthian type. On one side of the base of the column, there was a text which read as; (Posthumous, the prefect of Alexandria built it for the most just Emperor Diocletian).

In the middle ages, the crusaders believed that the head of Pompey, the Roman leader, was buried on the top of this column, and therefore they named it as Pompey’s pillar. But this is a misnomer because Pompey was killed in 48 BC, and this column was erected in 292 AD. Moreover the text on the base confirms that this column was erected for the Roman Emperor Diocletian.