In 2999 tgc, the various ascendant city-states in Thet collectively agreed to recognize Amounkoros Sidêreos (and later his descendants) as a unifying authority figure. This came at the end of several failed intergovernmental experiments of a more democratic nature, out of which the individual credibility of Amounkoros was virtually all that emerged unscathed.

The Sidêreos family rarely waded into politics, maintaining a level of participation only slightly above that of typical constitutional monarchs—for most of the dynasty's history, vetoes were used only once a decade on average. Partly this was because of the small parliament, which encouraged close ties between the single representatives of each province. Scholars often use the term litrabíste (oligarchy) to describe the political system, although it should not be conflated with the informal oligarchies that arise under the extremes of capitalism.

The Iron era is often remembered as a period of intense cultural sophistication and innovation, as the peace kept by the Sidêreos family precluded military ambition and left the aspiring with only constructive alternatives. This is not exactly an unbiased perspective—mainly it is born from the sharp contrasts with the violence, xenophobia, and gloom of the Gripsení period, but it is also a narrative pushed by monarchists like the Wanisinese and Illerans, who have much to gain from a non-pluralistic Thessian trading partner. More soberly, the culture of the Iron era should be regarded as a direct continuation to the Reed and Interim periods, although it is a fair criticism that the Interim was a time of uncertainty and instability.

The unbroken lineage of the Sidêreos family is quite remarkable, lasting until 5063 tgc when it was declared defunct by Sidêreon Sidêreos, who had spent his entire reign in exile from the palace in Regenelía.