From late 3rd century main concern securitas reiplubcicae security of state defence territory, population and fabric from internal and external attack concern for distribution of resources needed to support military effort. Persia: lack of resources both financial, skilled manpower, middle fourth century vulnerability northern frontier Diocletian ic notion of securitas differentiate territory integral to Roman state and territory that was not. Governments 4th and 5th centuries priorities, exp. Julian 363 and Constantine 336-7, defence what was conceived as Roman Territory. Norm in 4th and 5th, and despite publicists potential for expansion by direct military expansion abandoned.
Never gave up on abandoned or lost borders did not cease to be active beyond borders. By withholding military resources compelled by traditions of imperialism and achieving security to develop other means of pursuing objectives. Dev. 4th century political and politicized activity to replace military imperialism took a number of forms use of regular subsidies guaranteeing stable relationships, Christian missionaries, establishment of familial connections, exercise of degrees of suzerainty. Clear by 5th century more flexible instruments than military ones constraint by lack of resources and technological limitations of transportation and communication.
Yes cross border attacks (Con II and Celer into Arzanene 342 and 504 but mainly military extensions of the defence of the limes Even Julian's attempt can be seen as objective of compelling adherence to treaty of 299. Paying subsides even to differing groups cheaper than war, and attempts by Attila to extort with increasing demands rare. Political cost 3 main dangers: 1 attempt recipient to increase amount received 2. use of tribute as proof of subordination 3. internal support for regime cowardly and against tradition Persians and Attila only effective in the short-term, but Caucasus and Arab federates V effective. Damage control avoidance of paying subsides to avoid subordination, esp. in marginal areas like Mesopotamia or third parties trying to woo Publicists given role of explaining to people that Persia surrendered, philanthropic, civilizing virtues etc. panegyrics and panegyric ists Similar things in Persia no geographical conception of Borders but rather duty to look after Kings etc. direct military force only in threatening kings or exceptional circumstances.
Central authority and individual city or association done through embassies. Personal ruler to ruler experience useful ad against Romans getting 4/5 Armenia identified with Persians more than Romans - longer confederacies than Roman ones. Even in Northern Mesopotamia more ready to recognise sensibilities and cultivate loyalties with Syriac speaking peoples even encouraging Nestorian church D diocletian attempts to psl it hierarchy to allow war on two fronts 166 Danube and Samaritans, 3rd century Sasanians + Germans expansion military power. BUT Augustus still lacked capacity to wage war on two fronts. Division of a empire made recombination of armies impossible. Avoidance of war on two fronts during 4th century and afterwards almost military doctrine.
East Romans Balkans, Peris a, Arnica, occasionally WE and sometimes internal. Priscus and Joshua the Stylite make references to this. Many examples of this Theo II facing Attila and Gaiseric at same time, Justinian unable to properly fight Persians and Ostrogoths at same time. Similar in Persia King needed as figurehead, examples being 350 and 359 disengagement of Shapur II when conditions were favourable. And failure of Per oz to follow up military demands on Leo in 460 467.
Increase importance of on-military relations When enemy was perceived as stable, unlike BaBa and Huns more emphasis placed on political relationships - not just effectiveness but achievement of specific objectives. Treaty of 363 allowed political action to be carried out with expectation of some success. diplomacy could begin to work out own ground rules. Seen shifting military resources to Balkans and allowing material defences of the East to decay. Presentation other state, such as Ammianus Marcellinius, , praising certain aspects of life, present Persia as comprehensible and accessible, not just military target. Domestication of image creates necessary bridge. Terminology of relationships lamps, brothers or even unequal father son relationships in special cases.
Familial relationships both encourage and reflect real political advances Yezdegerd relationship with Thosdious father. not many marriages though. Armenians naturally toward Persians, still related, but from 3rd century to Christianization a lot were Roman looking. Important strategically as threatened interior and exterior both countries. Substantial military resources of had been utilised properly but chronic disunity.
Political settlement 387 one bought on themselves. Armenia may have caused some skirmishes 296-8 and 337 but pushed together two countries. Shapur and Theodosius I 387 settlement over Armenia no likely to be broken often. Evidence that Iberia and Laz ica as well as Armenia drew Persian and Roman together in discussion Mesopotamia always carved up had own identity language of Aramaic and culture through distinct Christianity distinct from orthodoxy of C acceptable to Persian Kings in 5th and 6th centuries Nestorianism became prevailing form of Mesopotamian Christianity continue to communicate across the border - Greeks at Antioch and C Nesotrian theological school at Edessa Christians freedom of movement between borders, although private travel happened, Empires not keen. Syriac population keen interest in relations between the two as battles fought in their city. Late Antiquity Persians treat them better, bur Shapur II persecution of Christians by Persians in 344 precluded any activity on other side of border.
Leaders on both sides tried to smooth the relationship. 400 Martha bishop of Sophanene, visiting Ctesiphon with a Roman embassy healed Yezdegerd I exploited for Christian church in Persia.