# Nicomedia, Trier, Milan, and Sirmium as tetrarchic capitals extract building and court costs from regions

Date: 293

## The fact

The tetrarchy sat in multiple capitals — Nicomedia, Trier, Milan, Sirmium — each a court to feed and fortify.

It is one event.

## Context

Regional courts can [shorten](/people/bill-shorten) administration (improving twin). This stores four palaces’ cost.

[Diocletian](/people/diocletian)’s documented role is bounded by other offices and collaborators named in the sources below. Sharing a field with them is not a reason to drop a documented act, and it is not a reason to assign later consequences done in the name after death.

Multiple residences. Nicomedia as Diocletian’s. Split palace is later retirement, another extraction.
Named person as heading of the dated public instrument. Later editors, museums, printers, or offices share publication. Complex where later carriers date the row.

## Evidence and sources

Cambridge and Britannica independently describe tetrarchic residences; Split is a later fifth palace in retirement.

Official or archival record: Cambridge Ancient History (https://www.cambridge.org/core/books/cambridge-ancient-history/; Cambridge University Press).

## Significance

Four courts are an inequality path of medium confidence on who paid.

Nicomedia is not Split’s UNESCO file. Keep 305 retirement.

Four courts are an inequality path of medium confidence on who paid.

## What is established and what is not

Established: multiple tetrarchic residences. Not established: a unique tax table per palace.

What would change the picture: a contradictory original with a different date or name, or a measured series that can be argued, with lag and alternatives, as a consequence of this instrument rather than of later institutions.

The date is the date of this instrument, not a licence to back-date every later harm or benefit.

Established here: a sourced, dated public instrument with a named contribution by Diocletian.

What would change the picture: a contradictory original with a different date, signatory, or non-occurrence; a demonstrated forgery; or a measured series that can be argued, with lag and alternatives, as a consequence of this instrument rather than of other causes.

They are not a public rating.

## People

- Diocletian: https://factrail.ai/people/diocletian

## Drivers

- Income Inequality: https://factrail.ai/drivers/income-inequality

## Sources

- https://www.britannica.com/biography/Diocletian
- https://www.cambridge.org/core/books/cambridge-ancient-history/

## Methodology

https://factrail.ai/methodology

Canonical: https://factrail.ai/facts/di-new-capitals-extraction