There are several indications of the ultimate origin of the Mandaeans. Early religious concepts and terminologies recur in the Dead Sea Scrolls, and Yardena (Jordan) has been the name of every baptismal water in Mandaeism. The Mandaic language is a dialect of southeastern Aramaic and is closely related to the language of the Babylonian Talmud. They formally refer to themselves as Nasurai (Nasoraeans). A priest holds the title of Rabbi and a place of worship is called a Mashkhanna. According to Mandaean sources such as the Haran Gawaita, the Nasurai inhabited the areas around Jerusalem and the River Jordan in the 1st century CE. There is archaeological evidence that attests to the Mandaean presence in pre-Islamic Iraq. Some scholars, including Kurt Rudolph, connect the early Mandaeans with the Jewish sect of the Nasoraeans.
It appears that Mani, the founder of Manichaeism, was partly influenced by the Mandaeans.
Early Persian periods
A number of ancient Aramaic inscriptions dating back to the 2nd century CE were uncovered in Elymais. Although the letters appear quite similar to the Mandaean ones, it is doubtful whether the inhabitants of Elymais were Mandaeans. Under Parthian and early Sasanian rule, foreign religions were tolerated. The situation changed by the ascension of Bahram I in 273, who under the influence of the zealous Zoroastrian high priest Kartir persecuted all non-Zoroastrian religions. It is thought that this persecution encouraged the consolidation of Mandaean religious literature.
The persecutions instigated by Kartir seems to temporarily erase Mandaeans from recorded history. Traces of their presence can still however be found in the so-called Mandaean magical bowls and lead strips which were produced from the 3rd to the 7th centuries.
The Mandaeans re-appear at the beginning of the Muslim conquest of Mesopotamia, when their "head of the people" Anush son of Danqa appears before Muslim authorities showing them a copy of the Ginza Rabba, the Mandaean holy book, and proclaiming the chief Mandaean prophet to be John the Baptist, who is also mentioned in the Quran. The connection with the Quranic Sabians provided them acknowledgement as People of the Book, people who followed a legal minority religion within the Muslim Empire. They appear to have flourished during the early Islamic period, as attested by the voluminous expansion of Mandaic literature and canons.
Tib near Wasit is particularly noted as an important scribal centre. Yaqut al-Hamawi describes Tib as a town inhabited by Nabatean (i.e. Aramaic speaking) Sabians who consider themselves to be descendants of Seth, son of Adam.
The status of the Mandaeans became an issue for the Abbasid al-Qahir Billah. To avoid further investigation by the authorities, the Mandaeans paid a bribe of 50,000 dinars and were left alone. It appears that the Mandaeans were even exempt from paying the Jizya, otherwise imposed upon non-Muslims.
Late Persian and Ottoman periods
Early contact with Europeans came about in the mid-16th century, when Portuguese missionaries encountered Mandaeans in Southern Iraq and controversially designated them "Christians of St. John". In the next centuries Europeans became more acquainted with the Mandaeans and their religion.
The Mandaeans suffered persecution under the Qajar rule in the 1780s. The dwindling community was threatened with complete annihilation, when a cholera epidemic broke out in Shushtar and half of its inhabitants died. The entire Mandaean priesthood perished and Mandeism was restored due only to the efforts of few learned men such as Yahia Bihram. Another danger threatened the community in 1870, when the local governor of Shushtar massacred the Mandaeans against the will of the Shah. As a result of these events the Mandaeans retired to the more inaccessible Central Marshes of Iraq.
Modern Iraq and Iran
Following the First World War, the Mandaeans were still largely living in rural areas in the lower parts of British protected Iraq and Iran. Owing to the rise of Arab nationalism, Mandaeans were Arabised at an accelerated rate, especially during the 1950s and '60s. The Mandaeans were also forced to abandon their stands on the cutting of hair and forced military service, which are strictly prohibited in Mandaenism.
The 2003 Iraq War brought more troubles to the Mandaeans, as the security situation deteriorated. Many members of the Mandaean community, who were known as goldsmiths, were targeted by criminal gangs for ransoms. The rise of Islamic Extremism forced thousands to flee the country, after they were given the choice of conversion or death. It is estimated that around 90% of Iraqi Mandaeans were either killed or have fled after the American-led invasion.
The Mandaeans of Iran lived chiefly in Ahvaz, Iranian Khuzestan, but have moved as a result of the Iran–Iraq War to other cities such as Tehran, Karaj and Shiraz. The Mandaeans, who were traditionally considered as People of the Book (members of a protected religion under Islamic rule) lost this status after the Islamic Revolution. Local authorities in Iranian Islamic Republic are known to encourage harassment and persecution of the Mandaeans. However, despite this, Iranian Mandaeans still maintain successful businesses and factories in areas such as Ahwaz. In April 1996, the cause of the Mandaeans' religious status in the Islamic Republic was raised. The parliament came to the conclusion that "Sabaeans" were included in the protected status of People of the Book alongside Christians, Jews and Zoroastrians and specified that, from a legal viewpoint, there is no prohibition against Muslims associating with Mandaeans, who are often regarded as being the Sabaeans mentioned explicitly in the Quran. That same year, Ayatollah Sajjadi of Al-Zahra University in Qom posed three questions regarding the Mandaeans' beliefs and seemed satisfied with the answers. These rulings however, did not lead to Mandaeans regaining their more officially recognized status as People of the Book.