The collapse of the Safavid dynasty in the 1720s ushered in a new round of conflict in Iraq that would continue through the first half of the 18th century. After the demise of Nāder Shah in 1747, however, a new, more stable relationship began to emerge between Persia and Iraq that reflected the development of regular diplomacy between Persia and the Ottoman empire. Three aspects of the diplomatic history of this frontier region during this era stand out as particularly important: (1) the turbulence that arose there with the rise of Nāder Shah; (2) the gradual regularization of diplomacy and relations between Persia and the Ottoman empire and their impact on Iraq; (3) the increasing importance of religious connections between Persia and Iraq during the Qajar era because of southern Iraq’s importance as a Shiʿite pilgrimage center.

From the fall of the Safavids through the rise of the Afsharids. At the beginning of the 18th century, Ottoman conflicts in Europe overshadowed relations with the Safavids. The Afghan invasion of Persia in 1722 ended two centuries of Safavid rule and focused Ottoman attention on the Persian-Iraqi border once again. The Ottomans themselves invaded Persia soon after this event to check the Russians, who had used turmoil there as a pretext to advance southwards. By 1724, the Turks had secured control of Persian territories in Azerbaijan and the Caucasus. They arranged a peace treaty with the Russians to partition the northwestern provinces of Persia, curtail any more foreign incursions into Persia, forestall the Afghans, and maintain a vestigial Safavid state in power (Hurewitz, I, pp. 65-69).

The Ottomans soon confronted the Afghans in battle, however, as the latter gained more power over Persia, and Ottoman governors in Iraq played an important role in efforts to keep the Afghans in check. An Ottoman campaign against the Afghan ruler of Persia, Shah Ašraf Ğelzī, was coordinated by Aḥmad Pasha, the semi-autonomous Ottoman Mamluk governor of Baghdad (r. 1724-47), but this culminated in a severe defeat at Ḵorramābād for the Ottoman army in November 1726 (Lockhart, 1958, pp. 287-91).

By the late 1720s, Nāder Shah (then known as Ṭahmāsp-qoli Khan) was rising to power as a Safavid general. His defeat of Ašraf at Mehmāndust in September 1729 marked the end of Afghan power in Persia. After he had vanquished the Afghans, Nāder moved against the Ottomans and succeeded in temporarily seizing parts of northern Iraq for a period of time in the early 1730s, briefly placing Baghdad under siege. Based on this success, he conducted peace negotiations with Aḥmad Pasha, who was disposed to give Nāder favorable terms due to his growing record of military success. Aḥmad was constrained, however, by his sovereign, the new Ottoman Sultan Maḥmud I (r. 1730-54), who faced considerable domestic pressure not to be lenient with Persia, the home of the Ottomans’ longtime Shiʿite foes (Tucker, 2006, p. 30).

Following his own coronation as Persia’s ruler in 1736, Nāder sent an embassy to Istanbul to present a novel peace plan to the Ottomans. He requested that they accept Twelver Shiʿism as a fifth legitimate school (to be known as the Jaʿfarī maḏhab) of Sunnite Islam and asked for other provisions to secure the legal status of Persians in Ottoman territory. In all subsequent discussions with him, the Ottomans expressed their willingness to recognize formally the status of Persians in their domains as fellow Muslims within the confines of the existing status quo, but continually rejected his novel religious proposals as unwarranted innovations (Tucker, 2006, pp. 45-58).

In the face of Ottoman intransigence, Nāder shifted to pursuing the Afghans on his eastern flank, a campaign that ultimately led to his successful conquest of India and Turkistan. This adventure left him as the ruler of a vast, expanded empire, and soon after he returned home, Nāder embarked on another short campaign against the Ottomans in Iraq as part of a new attempt to get them to accept his religious proposals. He briefly placed Mosul and Basra under siege again in 1743. Upon lifting the blockade of Mosul, he convened a conference of Ottoman and Persian clerics in the shrine city of Najaf. Although this meeting produced a written agreement in which those attending affirmed his Jaʿfarī maḏhab concept, the sultan still would not ratify it (for the versions of its text, see Sowaydi, pp. 23-25; Estrābādi/Astarābādi, 1962a, pp. 388-89; idem, 1962b, pp. 596-601; Eqbāl, pp. 48-55; Lockhart, 1938, pp. 232 ff.; Tucker, 2006, pp. 79 ff.).

Nāder fought the Ottomans in Iraq and the Caucasus for three more years with minimal success. In the end, he finally agreed to drop his religious proposals and signed the Kordān agreement with them on 19 Šaʿbān 1159/6 September 1746. This treaty reestablished the 1639 Ottoman-Persian border without large territorial changes and, like earlier agreements, prohibited such overt anti-Sunnite practices in Persia as the cursing of some of the “rightly-guided” (rāšedun) caliphs and Companions of the Prophet. It had important consequences for Iraq, however, because it asserted in a more specific way than ever before the sultan’s responsibility to protect the rights of Persian visitors in Ottoman lands, particularly pilgrims to Shiʿite tombs and shrines in Iraq. Although Nāder was assassinated soon after the agreement was signed, its basic terms remained in force even during later episodes of renewed conflict (Daftar-e moṭālaʿāt-e siāsi, pp. 290-91, Pers. text; Hurewitz, I, pp. 79-80; Lockhart, 1938, pp. 254-56; Moḥammad-Kāẓem Marvi, III, pp. 1180-81). During the turbulent era in Persia from the fall of the Safavids through the reign of Nāder Shah, continuity in Persian-Iraqi relations at more mundane levels was provided by successive administrations of the Georgian father and son, Ḥasan and Aḥmad Pasha, the so-called Mamluk Pashalik of Baghdad, who ruled in Baghdad between 1704 and 1747 in collaboration with a group of long-established notable Sunnite families there. Prominent Iraqi families from the full spectrum of religious communities in the three main Ottoman Iraqi provinces of Mosul, Baghdad, and Basra continued to pursue trade with Persia during this era despite intermittent episodes of conflict (Longrigg, p. 47; Abdullah, pp. 99-104).

The next significant military clash in Iraq occurred under Karim Khan Zand, who had become the ruler of the southwestern part of Persia in the wake of the collapse of the Afšār dynasty. His forces, led by Ṣādeq Khan Zand, occupied Basra in Rabiʿ I 1190/April 1776 after a long siege (Ḡaffāri, pp. 321-52; Perry, pp. 167-83, 192-98). The Ottomans had gone to great lengths to avoid deploying troops to defend Iraq, but were forced to mobilize there in 1778 to recapture Basra from the Persians. This conflict was transient, however, because a process of diplomatic change that began during Nāder’s reign resulted over the next several decades in the development of a new de jure framework for Ottoman-Persian relations.

Despite the occasional outbreak of hostilities between Persia and the Ottoman empire as well as the often tense atmosphere surrounding Shiʿite pilgrimages to Iraq’s shrine cities that sometimes caused urban unrest (see Cole and Momen), the Ottomans allowed the Shiʿite culture of southern Iraq to flourish and even to expand with growing numbers of shrine visitors from Persia. South Iraq had always been a major pilgrimage center for Shiʿites across the Islamic world (see ʿATABĀT). As the Ottomans began to collect significant revenue from these pilgrims and from fees paid to transport corpses to be buried in the holy cities of Najaf and Karbalāʾ, they adopted a fairly tolerant approach to Shiʿite piety and to the spread of Shiʿism there despite their ostensible role as defenders of Sunnite Islam.

Ottoman tolerance of the growth of Shiʿite influence in southern Iraq was revealed most clearly by how they permitted the construction of the Hendiya canal. The Hendiya canal, built between 1785 and 1803 with a large contribution from the Shiʿite rulers of the Indian state of Awadh (Oudh), was designed to bring more water from the Euphrates river to Najaf for the growing number of pilgrims there (Cole). Prominent Persians such as Moḥammad-Esmāʿil Khan Wakil-al-Molk Nuri, a late 19th-century governor of Kermān, also funded such projects, sponsoring the construction of canals around Najaf and other improvement projects (Pirzāda, II, pp. 346-47; Nakash, 1994, p. 448).

Iran-Iraq relations were also affected in the 19th century by the sedentarization of tribes in southern Iraq. Connections were made by Shiʿite clerics whom the Otto-mans allowed to proselytize in the region between the shrine cities and new farming areas, which increased the Shiʿite population there substantially by the middle of the 19th century. Among the most important of these groups was the large and diverse tribal confederation of southern Iraq known as the Montafeq (Nakash, 1994, pp. 25-48).

Changes in the relationship between Persia and Iraq in the Qajar era can also be perceived in the last substantial military conflict between the Ottomans and Persia in the early 1820s. It erupted, as had previous confrontations, due to tension that arose among groups living on the Persia-Iraq border and as an indirect consequence of increased European presence in the area. In contrast to previous hostilities, Ottoman clerics issued no anti-Shiʿite fatwās at all to justify the conflict. When peace negotiations commenced, the Ottoman Šayḵ-al-Eslām wrote a letter to the Qajar crown prince ʿAbbās Mirzā, who led the Persian army, extolling the basic friendship between their nations and describing them as “two great countries that are as one body” (Cevdet, XII, p. 254). The Erzurum treaty of 19 Ḏu’l-qaʿda 1238/28 July 1823 that ended this military confrontation explicitly reconfirmed the provisions of the 1746 treaty and extended the formal legal recognition of the personal status of Persians in the Ottoman empire even more than before, including a section, for example, providing detailed instructions for the disposition of the estates and property of Persians who died there (for the text, see Daftar-e moṭā-laʿāt-e siāsi, pp. 294-98; Eʿteżād-al-Salṭana, pp. 368-71; Hedāyat, IX, pp. 625-29; Hurewitz, I, pp. 219-21).

However, since hostile incidents continued to erupt along this border over the next twenty years, an international peace conference was convened in 1843 at the behest of the Russians and the British. It resulted four years later (1847) in a second Treaty of Erzurum (Daftar-e moṭālaʿāt-e siāsi, pp. 323-25; Ādamiyat, pp. 62 ff.; see also BOUNDARIES i). In this agreement, the Persia-Iraq land boundary was demarcated far more specifically than in any previous treaty, but it still did not clearly address the question of jurisdiction over the waters of the Šaṭṭ-al-ʿArab river. Negotiations continued for years on this issue, but since neither side had enough incentive to resolve this issue, the British Foreign Secretary, Lord Palmerston, commented in 1851 that “the boundary line between Turkey and Persia can never be finally settled except by an arbitrary decision on the part of Great Britain and Russia,” presaging many decades of discussion. In the end, the Ottomans and Qajars were induced under European pressure to agree to a boundary line formalized in the Constantinople Protocol of November 1913, but this conflict flared up again long after the end of both dynasties and more agreements had been signed, with Iraq invading Persia in 1980, partially as a consequence of this unresolved issue (see Edmonds, and vii, below).

In contrast, agreements about the status of Persians and Ottomans in each other’s territories were far more productive, with each successive accord establishing a more solid basis for Persians and Iraqis to travel with ease between the two countries. By 1875, Persia was allowed to set up consular courts in Ottoman territory just as the Europeans had done (Masters, p. 15). According to one late 19th-century Persian account, if a case were brought before these courts involving two Muslim Persians, it would be “treated according to the laws of the Prophet Muhammad,” indicating how Persia had become officially recognized in Ottoman eyes as an autonomous, yet still Islamic, legal jurisdiction. (Farāhānī, p. 143).

Nevertheless, the more stable Ottoman-Iranian relationship of this era did not mean the end of tension and conflict between the two powers. Great upheavals periodically arose in 19th-century Iraq as the result of episodes of discontent among the Shiʿite population there (see Deringil as well as Cole and Momen). Iranian pilgrims still sometimes received very rough treatment from Sunnites on their journeys even into the late 19th century (Peters, pp. 176-80). In addition, marriages between Sunnites and Shiʿites remained legally forbidden for the duration of the Ottoman empire (Krüger, pp. 146-47).

In the end, although the overall stability of Persia-Iraq relations that had emerged during the Qajar period was severely challenged by the cataclysmic events of the 20th century, particularly World War I and the explosion of nationalisms in the region, the parameters of ordinary interaction between the two areas that had been established in the 19th century prevailed for a long time. Despite enormous changes, the tolerance of Shiʿism that the Ottomans began to show in Iraq in the late 18th century allowed Shiʿites there to build and sustain connections with Persia that survived through the great upheavals of the 20th century, such as the Iran-Iraq War of 1980-88.