Domain

A domain was an administrative unit of Covenant territory. In their current incarnation, domains came into being in the Consolidation Era of Covenant history (c. 1800 — 2552 CE).

In most cases, High Charity did not directly govern individual worlds of the Holy Ecumene, for the Covenant Empire was far too vast for that to be viable. Instead, regional administration was handled by provincial domains, which encompassed anywhere from dozens to hundreds of Covenant worlds, all governed from a provincial hub-world or station. The borders of domains were defined by astrographic, cultural, historical and/or political factors, the most notable being the local base worlds' ability to project power. Domains had their own governments with varying degrees of autonomy from High Charity, though the trend in the latest centuries of Covenant history was toward increased centralization of power and standardized government structures. The preceding Feudal Era had seen considerable decentralization of military, political and even religious power under various regional lordships, a development that High Charity would ultimately reverse in the series of sweeping political and military reformations known as the Second Illumination.

Types
The Covenant Ministry of Integrity's categorization system recognized two main types of domain:

Primary domains
Primary domains were defined by both their direct administrative relationship to High Charity. They could comprise up to hundreds of officially-recognized worlds, though only a portion of these were governed directly by the domain's synodic authorities, with the majority falling under various feudal secondary domains which then paid tithes and tribute to the primary domain's government, which was in turn responsible for tithes to High Charity. Primary domains were governed from the most politically and militarily notable worlds or world-stations of a given region; these were also known as cathedrae or synod-worlds.

The most common types of primary domain were ordinariates or mixed dioceses, governed by a San'Shyuum official known as a magistrate and a council of regional authorities known as a synod. The San'Shyuum magistrate typically also served as the archbishop of the regional churches, though customs varied. In addition, primary domains established around major reliquary sites since the Second Illumination were often full-fledged dioceses, governed near-exclusively by religious authorities with direct ties to High Charity; this was to prevent regional lords from hoarding artifacts to themselves, which had occurred various times in the preceding ages. However, most primary domain capitals, whether full dioceses or not, were defined as local nexuses of artifact collection, and partly drew their legitimacy not only from commercial and military power, but also the presence of holy relics.

The primary domains were overlaid on older, more complex and varied territorial units, many of which retained varying degrees of autonomy even after the reforms, and ended up complicating regional administration even further. Over time, many of the primary domains began to resemble the very states they were meant to replace in terms of regional variety and bureaucratic complexity. Primary domain administrations near the Primeval Core were often less powerful, with the lesser domains there being much more prominent due to their age and well-established power bases. In such regions, the primary domain authorities were little more than rubber stamps while most of the power was in the hands of local lords. More recent domains further out from the core were often more centralized in their power structure, with less power allocated to feudal lords. In recent ages, the trader class has also begun to hold considerable sway in certain further-out domains, particularly on the galactic spinward side; this development has only been intensified by the Great Schism.

Some domains have remained as political units following the Great Schism, especially those with lasting historic foundations and relative cultural unity. However, the older lesser domains have generally endured the Schism better than the more recent and partly artificial primary domains, as their bonds were stronger and more culturally established. Regardless, even with many synodic governments destabilized, destroyed or ousted, the primary domains remain relevant as territorial identifiers, though some regions have since reverted to using even older astrographic names and political divisions.

Secondary domains
Also known as lesser domains, secondary domains were lesser polities administrated by the synodic governments of primary domains. These were highly eclectic in terms of governance, ranging from Sangheili lordships and their vassals to thrall-worlds, merchant republics and freeholds. Many of these polities predate the Second Illumination, though others were also merged or created during the conflicts of that era. Many secondary domains have survived into the post-Schism era more or less intact.