The Kingdom of Ormus (also known as Ohrmuzd, Hormuz, and Ohrmazd; Arabic: هرمز, Portuguese: Ormuz) was a 10th- to 17th-century kingdom located within the Persian Gulf and extending as far as the Strait of Hormuz. The Kingdom was established by Arab princes in the 10th century who in 1262 came under the suzerainty of Persia, before becoming a client state of the Portuguese Empire.
The kingdom received its name from the fortified port city which served as its capital. It was one of the most important ports in the Middle East at the time as it controlled seaway trading routes through the Persian Gulf to India and East Africa. This port was located on Hormuz Island, which is located near the modern city of Bandar-e Abbas.
The Strait of Hormuz is a narrow, strategically important waterway between the Gulf of Oman in the southeast and the Persian Gulf in the southwest. On the north coast is Iran and on the south coast is the United Arab Emirates and Musandam, an exclave of Oman.
The city-state of Ormus dates back to the 13th century when it controlled the slave market from Africa and Arabia to Khorasan in Persia. At its zenith in 13th to 14th century, Ormus (or Ormuz) was a powerful naval state with a large and active trading fleet and a powerful navy. Petrashevsky reports the size of the fleet to be up to 500 fighting ships. These ships were not armed with cannons.
The original city of Hormuz was situated on the mainland in the province of Mogostan of the province of Kirman. It was destroyed, date uncertain, either by one of the princes of the Kirman Seljuk, or by the Mongols. At this time (c. 1301) the inhabitants moved to the neighbouring island of Jerun.
There are three periods in the history of the Kingdom of Ormus: First Mohammed Diramku migrated from Oman to the Iranian coast in the eleventh century. The capital was transferred to the island of Hormuz in the fourteenth century. In the second period, the island of Hormuz eclipsed the commercial power of the island of Kish. Hormuz become the greatest emporium in the Persian gulf. The last period begin with the attack of the Portuguese of Alfonso of Albuquerque. 
It was during the reign of Mir Bahdin Ayaz Seyfin, fifteenth king of Hormuz, that Tartars, raided the kingdom of Kerman and from there to that of Hormuz. The wealth of Hormuz attracted raids so often that the inhabitants sought refuge off the mainland and initially moved to the island of Kishm. Mir Bahdin then visited the island of Jerun and obtained it from Neyn, King of Keys, to whom all the islands in the area belonged. 
Abbé T G F Raynal gives the following account of Hormuz in his history:
Hormúz became the capital of an empire which comprehended a considerable part of Arabia on one side, and Persia on the other. At the time of the arrival of the foreign merchants, it afforded a more splendid and agreeable scene than any city in the East. Persons from all parts of the globe exchanged their commodities and transacted their business with an air of politeness and attention, which are seldom seen in other places of trade. The streets were covered with mats and in some places with carpet, and the linen awnings which were suspended from the tops of the houses, prevented any inconvenience from the heat of the sun. India cabinets ornamented with gilded vases, or china filled with flowering shrubs or aromatic plants adorned their apartments. Camels laden with water were stationed in the public squares. Persian wines, perfumes, and all the delicacies of the table were furnished in great abundance, and they had the music of the East in its highest perfection … In short, universal opulence, an extensive commerce, politeness in the men and gallantry in the women, united all their attractions to make this city the seat of pleasure.
It was during the Portuguese occupation of the island that the Mandaeans first came to western attention. The Mandaeans were fleeing persecution in the vilayet of Baghdad (which, at the time, included Basra) and Khuzestan in Iran. When the Portuguese first encountered them, they mistakenly identified them as "St. John Christians", analogous to the St. Thomas Christians of India. The Mandaeans, for their part, were all too willing to take advantage of the confusion, offering to accept papal authority and Portuguese suzerainty if the Portuguese would invade the Ottoman Empire and liberate their coreligionists. The Portuguese were attracted by the prospect of what appeared to be a large Christian community under Muslim rule. It was not until after the Portuguese had committed themselves to the conquest of Basra that they came to realize that the Mandaeans were not what they claimed to be.
As vassals of the Portuguese state, the Kingdom of Ormus jointly participated in the 1521 invasion of Bahrain that ended Jabrid rule of the Persian Gulf archipelago. The Jabrid ruler was nominally a vassal of Ormus, but the Jabrid King, Muqrin ibn Zamil had refused to pay the tribute Ormus demanded, prompting the invasion under the command of the Portuguese conqueror, António Correia. In the fighting for Bahrain, most of the combat was carried out by Portuguese troops, while the Ormusi admiral, Reis Xarafo, looked on. The Portuguese ruled Bahrain through a series of Ormusi governors. However, the Sunni Ormusi were not popular with Bahrain's Shia population which suffered religious disadvantages, prompting rebellion. In one case, the Ormusi governor was crucified by rebels, and Portuguese rule came to an end in 1602 after the Ormusi governor, who was a relative of the Ormusi king, started executing members of Bahrain's leading families.
After the Portuguese made several abortive attempts to seize control of Basra, the Safavid ruler Abbas I of Persia conquered the kingdom with the help of the English, and expelled the Portuguese from the rest of the Persian Gulf, with the exception of Muscat. The Portuguese returned to the Persian Gulf in the following year as allies of Afrasiyab, the Pasha of Basra, against the Persians. Afrasiyab was formerly an Ottoman vassal but had been effectively independent since 1612. They never returned to Ormus.
Situated between the Persian Gulf and the Indian Ocean, Ormus was a "by-word for wealth and luxury", perhaps best captured in the Arab saying: "If all the world were a golden ring, Ormus would be the jewel in it". The city was also known for its licentiousness according to accounts by Portuguese visitors; Duarte Barbosa, one of the first Portuguese to travel to Ormuz in the early 16th century found:
|“||The merchants of this isle and city are Persians and Arabs. The Persians [speak Arabic and another language which they call Psa], are tall and well-looking, and a fine and up-standing folk, both men and women; they are stout and comfortable. They hold the creed of Mafamede in great honour. They indulge themselves greatly, so much so that they keep among them youths for the purpose of abominable wickedness. They are musicians, and have instruments of diverse kinds. The Arabs are blacker and swarthier than they.||”|
|“||Its moral state was enormously and infamously bad. It was the home of the foulest sensuality, and of all the most corrupted forms of every religion in the East. The Christians were as bad as the rest in the extreme license of their lives. There were few priests, but they were a disgrace to their name.
The Arabs and the Persians had introduced and made common the most detestable forms of vice. Ormuz was said to be a Babel for its confusion of tongues, and for its moral abominations to match the cities of the Plain. A lawful marriage was a rare exception. Foreigners, soldiers and merchants, threw off all restraint in the indulgence of their passions ... Avarice was made a science: it was studied and practiced, not for gain, but for its own sake, and for the pleasure of cheating. Evil had become good, and it was thought good trade to break promises and think nothing of engagements ...
Ormus is mentioned in a passage from John Milton's epic poem Paradise Lost (Book II, lines 1–5) where Satan's throne "Outshone the wealth of Ormus and of Ind", which Douglas Brooks states is Milton linking Ormus to the "sublime but perverse orient". It is also mentioned in Andrew Marvell's poem 'Bermudas', where pomegranates are described as "jewels more rich than Ormus." In Hart Crane's sonnet To Emily Dickinson, it appears in the couplet: "Some reconcilement of remotest mind– / Leaves Ormus rubyless, and Ophir chill." The closet drama Alaham by Fulke Greville is set in Ormus.