May 11, AD 330

Constantinople

Constantine formally dedicates Constantinople

At the center of the ceremony stood a seven-drum porphyry column crowned by Constantine as a rayed sun emperor, spear in one hand and globe in the other.

Monday, 11 May 330

Constantine formally dedicated the rebuilt and greatly expanded city of Byzantium as Constantinople on Monday, 11 May 330.

A late-antique chronicle says he endowed the city with a senate, gave it his own name, and proclaimed it a "second Rome."

Major construction had begun in November 324, about five and a half years earlier — an interval conventionally rounded up to six years.

The column in the new forum

The opening ritual centered on the new Forum of Constantine, where the porphyry column and its colossal imperial statue dominated the space: Constantine represented as Helios.

The column was already standing by about 328. It commemorated the foundation and gave it a focal point, but a separately documented dedication of the monument on 11 May is not secure.

Seven porphyry drums survive in the shaft, which now rises about 35.8 metres above the pavement; the original column, without its statue, is estimated at 37 to 40 metres.

What the ceremony did not do

It did not create a separate Eastern Roman Empire. The Roman state remained one, and the conventional eastern/western division belongs to later history; Constantinople's growth into the regular imperial capital continued over subsequent decades.

It also did not make "Nova Roma" the city's official name. A scholarly study finds no evidence that was ever the official Constantinian name — "New Rome" and "Second Rome" were rhetorical descriptions, with official ecclesiastical use developing after 381.

The detailed descriptions of the rites come from sources written centuries afterward and contain legendary material. Claims about relics within or beneath the column are late traditions, and twentieth-century investigation found no such repository.

Sources

Researched 23 Aug 2026 6 sources 2 audit passes, 1 issue open

How this was checked

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What the sources leave uncertain

The date is well supported, including by the seventh-century Chronicon Paschale, but detailed descriptions of the rites come from sources written centuries afterward and contain legendary material.
A scholarly study finds no evidence that “Nova Roma” was ever the city's official Constantinian name; “New Rome” and “Second Rome” were rhetorical descriptions, with an official ecclesiastical use developing after 381.
The column and statue appear to have been erected around 328. It is safer to say that they participated in or commemorated the 330 city dedication than that Constantine separately dedicated the monument that day.
Claims about pagan and Christian relics beneath or within the column are late traditions; twentieth-century investigation found no such repository.