Chalcedon is governed by a plutocratic oligarchy with two major ruling bodies: the single and broadly autocratic Archon, and the council of Archporos (rulers of the strait).

The body of Archporos is made up of all living individuals who have previously served in the Archonship. Their foremost role is as a judicial body, trialing lawbreakers and meting out justice as they see fit. Moreover, each Archporos serves in an advisory role to the Archon, who frequently employs them in important matters of state such as diplomatic missions and presiding over tax collection. They also act as an upper house for new legislation, tempering the power of the Archon.

The Archon, elected on a yearly cycle by the body of Archporos, is in one man the executive and legislative body of Chalcedon. With the personal power to draft and enact laws and complete authority over Chalcedon's army as commander-in-chief, the Archon's first role is to ensure that Chalcedon remain on a path of progress, working towards a fixed goal in mind.

Although technically any man may be elected Archon, in practice the Archporos without exception elect the Archon either from among their own number or from the families of existing Archporos. In this fashion both ruling bodies are effectively controlled by a small handful of the wealthiest families within Chalcedon, and the Archonship tends to sway towards those whose families have gone the longest since last holding the office or whose families can currently call upon the most favours from the other wealthy houses. Only rarely does actual merit come into it.

Each Archon can serve a maximum of three consecutive terms, a measure undertaken to ensure that no Archon can consolidate power to the point of becoming a tyrant, as was documented surely after the time of Alexander the Great. In addition, no Archon can serve more than six years in any ten. Archons are audited by the Archporos when they retire from the position to ensure that their office was not a corrupt one - though this practice has very much become one of rubber-stamping rather than genuine inquiry into wrongdoings (which could easily be found). Finally, the two powers convene in councils whenever new legislation or serious foreign policy decisions are at hand. Although the Archon has sole authority to draft legislation, a supermajority vote of two-thirds of the Archporos can veto any given decision of the Archon. Furthermore in practice, the family of the presiding Archon is frequently the true author of the legislation present at such ruling councils, and the Archon frequently defers to the general will of the Archporos without any individual matter being put to formal vote, a practice largely resulting from the inevitable new-electee if any Archon oversteps their power. Nevertheless, popular and competent Archons rarely find the Archporos a serious impediment to their designs.

Any lower officials such as diplomats on minor delegations, tax collectors, public auditors, strategoi and harbourmasters are appointed with a strong preferential bias to the extended families of the ruling families. However merit occasionally slips through the cracks in the plutocracy, and talented civilians from all social classes have been known to serve in all positions save those of the Archonship and Archporos themselves.

The year 270BC is known in Chalcedon as 'Chares I', the first year in which Chares of the house Thanos is elected Archon. His family is among the wealthiest in Chalcedon, and owes the bulk of its fortunes to its privately owned trade vessels.

[Since sources do not really exist for Chalcedon's government, I've taken the general theme of Oligarchy common in this time period/region and ran with it. As such, the above is an informed fabrication rather than an attempt at complete historical veracity.]