Decree of Heideran VII
In mid-YC105, Emperor Heideran VII issued a decree limiting the use of military force in space to the Amarr Imperial Navy. As initially stated, during a meeting of the Imperial Privy Council at which Emperor Heideran VII was personally present, the decree restricted space fleets solely to the Imperial Navy. This extraordinary measure was evidently intended to concentrate control of space within the Amarr Empire in the hands of central government forces answering directly to the Emperor.
In practice, the "Heideran Decree" began to be watered down almost as soon as it was promulgated as Imperial law, and its immediate implementation would have been all but impossible for practical purposes. This was primarily due to the extent to which the Amarr Empire relied for security and patrolling coverage on the fleets maintained by the Royal Houses, vassal houses, certain military orders and a number of imperial institutions.
Reign of Doriam II
By the time Heideran VII died in late August YC105, the work of transferring fleet assets to the Imperial Navy and re-organizing various fleet command structures had barely begun. With the succession of Doriam II, the implementation of the Heideran Decree continued but had its largest impact on minor houses and fleets held independently by various imperial institutions.
As such, the Imperial Chancellery fleet was broken up and distributed among the numbered fleets of the Imperial Navy, and the surprisingly powerful Ministry of Assessment fleet met a similar fate. A large number of minor house fleets were seized and transferred to the Imperial Navy. The Royal Houses, for the most part, were able to delay the process of transfer when it came to their own fleets and Emperor Doriam II was not minded to press the issue given so many other matters to deal with during the transition from Heideran's long rule.
As the Ministry of War was occupied with a significant amount of work managing the process, a major means by which certain powerful interests retained functioning fleets was to redesignate them as "police", "customs" or "border militia" forces. The Ministry of Internal Order was able to successfully preserve almost the entirety of its fleet by arguing that its police and internal security functions required it to have direct access to such a fleet. The Theology Council was less successful in this regard but retained a significant escort and light security fleet. In practice, most imperial institutions retained a large number of cruisers and frigates for escort and other light duties.
The Karsoth Interregnum
Under Doriam II, the Royal House fleets were being prepared for relisting as police and border forces, and this continued under the "Karsoth Interregnum" following Doriam's assassination in July YC107. As a matter of fact, Court Chamberlain Dochuta Karsoth's strategy for delaying an imperial succession, so that he could maintain power over the central government, included handing significant concessions to the Royal Houses in their own territories. As a result, the Heir fleets grew in some cases and the "police and border" forces maintained by the Royal Houses easily became fully as powerful as they were before the Heideran Decree.
During the Interregnum period, a significant number of vassal houses were permitted to maintain fleets for police, security and border duties. This was a particularly common practice where vassal houses controlled the holdership of constellations and especially in border zones far from the primary holdings of Royal Houses. As is typical during any period of the Amarr Empire's history – and was even more the case during the unsettled confusion of the Karsoth Interregnum – there were many exceptions to this situation in both directions.
Reign of Jamyl I
When Empress Jamyl I came to power in YC110, the situation was slowly regularized somewhat, with the basic authority of the Imperial Throne and the specific powers of the Heideran Decree reinforced anew, within newly interpreted limits. The old "police and border forces" compromise was settled on as a reasonable balance between central Imperial authority and the reality that the Royal Houses and border Holders needed some means of enforcing their rights under Imperial and local law, while maintaining local security according to their duties as Holders.
Notwithstanding the confiscation of the House Kador fleet, after a renegade incursion into Solitude in November YC110, the reign of Empress Jamyl I was marked by a formalized relaxation of the Heideran Decree, recognizing the delicate balance of power required to maintain the Amarr Empire's political cohesion. Given one of the hallmarks of Empress Jamyl I's brief reign was a consolidation of the Amarr Empire and associated territories, such as the Ammatar Mandate and Khanid Kingdom, into a closer political union, the new approach to the Heideran Decree was in line with her goals. It is notable that even the Kador fleets were partially restored to that Royal House by the end of her reign. Additionally, certain imperial institutions were permitted a limited restoration of their fleet capability, the most notable example being the Imperial Chancellery fleet.
Reign of Catiz I
Under Catiz I, the revised Heideran Decree, as interpreted and issued as law by Empress Jamyl I, has been maintained as the status quo. Many minor houses continue to be forbidden the use of space fleets that could be considered military in nature by the standards of the Amarr Empire. The typical situation is that any capability beyond the escort and security needs appropriate to the scope of a minor holder's demesne is prohibited. This had always meant holdings of planetary scale and smaller having extremely limited capacity for undertaking space combat, and this remains true in the great majority of cases. Holdings that encompass multiple celestial bodies will usually have greater capability the larger the scale of the territory concerned. The most powerful minor house fleets are found in border systems and especially under the control of minor houses who have constellation-scale holdings in border regions.
The status of the Royal House fleets remains stable under the old compromise and they constitute some of the most powerful fleets in the Amarr Empire. Almost all minor house fleets of any account are controlled by vassals of the Royal Houses, and are usually integrated into the command and control structure of their liege house's police and border force. Some minor houses are direct vassals of the Imperial Throne and if such houses maintain fleets of significance these are usually integrated into the local Imperial Navy fleet's command as a militia force.
A number of loopholes in the Heideran Decree were variously explicit or implicit in imperial law from the very beginning, and most remain in place. The major loophole that has been made use of by minor houses from time to time is the very large number of military orders and chartered mercenary companies that exist within the Amarr Empire. A significant number of theses entities are permitted space fleets and furthermore may hire these out, or otherwise provide them, to Holders.
Other loopholes include the right of certain religious orders to defend themselves in any time and place throughout the Amarr Empire, clever interpretation of which has occasionally served its purpose, and perhaps most significantly, and ironically given the date of the Heideran Decree, the ability of capsuleers to maintain very powerful military forces within the Amarr Empire due to the provisions of the Yulai Accords and Convention.
On YC121.09.27, the third anniversary of the coronation of Empress Catiz I, the Heideran Decree was revoked in its entirety by order of the Empress. The revocation accompanied a major territorial and military reorganization of the Amarr Empire.