Before the Iran war, how empires fought for the Strait of Hormuz

Since late February 2026, the Strait of Hormuz has been effectively blocked to commercial shipping following the outbreak of the Iran-US-Israel conflict, tri...

What Happened

Since late February 2026, the Strait of Hormuz has been effectively blocked to commercial shipping following the outbreak of the Iran-US-Israel conflict, triggering a global oil supply crisis and price surge.
Iran's Islamic Revolutionary Guard Corps (IRGC) has attacked and boarded merchant vessels and laid sea mines in the strait — the first significant physical closure of the strait since it became central to global energy supply chains.
Brent crude prices jumped 8% immediately (from USD 71.32 to USD 77.24 per barrel) and have subsequently exceeded USD 100 per barrel, reflecting the strait's irreplaceable role in global energy trade.
Iran has demanded international recognition of sovereignty over the strait, proposing a USD 2 million per tanker toll — an unprecedented claim framed in terms of historical rights.
The 2026 crisis has renewed academic and policy interest in the long history of imperial contestation for control of the Hormuz straits.

Static Topic Bridges

Geography of the Strait of Hormuz

The Strait of Hormuz is a narrow waterway connecting the Persian Gulf to the Gulf of Oman, which opens into the Arabian Sea. It is flanked by Iran on the northern (eastern) coast and the Musandam Peninsula (a part of Oman, separated from the main Omani territory) on the southern coast. At its narrowest, the strait is approximately 33–39 kilometres (20–24 miles) wide, with two unidirectional shipping lanes of 3.2 km each, separated by a 3.2 km buffer zone.

The strait contains eight major islands; seven are controlled by Iran (including the contested Abu Musa, Greater Tunb, and Lesser Tunb, which Iran seized from the UAE in 1971).
Total length of strait: approximately 167 km (104 miles).
The strait serves as the only maritime exit route for several Persian Gulf states: UAE, Qatar, Bahrain, Kuwait, and Iraq have no alternative sea access.
Approximately 20 million barrels of oil per day (about 20% of global seaborne oil trade) transited the strait in 2024; 84% of crude oil through the strait is destined for Asian markets, with China receiving approximately one-third of its oil via this route.
Alternative routes: UAE's Abu Dhabi Crude Oil Pipeline (capacity: 1.5 million barrels/day); Saudi Arabia's East-West Pipeline (Petroline, capacity: 5 million barrels/day); these can partially offset a closure but not replace full transit.

Connection to this news: The Strait's extreme narrowness and lack of alternative routes for multiple Gulf states means that even partial interdiction by Iran's naval forces creates immediate global energy market disruption.

Historical Contestation: Empires and the Kingdom of Hormuz

The Strait of Hormuz has been a pivot of world trade for over two millennia. The ancient city and island of Hormuz (on the modern Iranian coast) served as a terminus of overland Silk Road trade routes and a transshipment hub between the Persian Gulf and the Indian Ocean trading world.

Alexander the Great's admiral Nearchus conducted the first recorded survey voyage from the Indus back to Susa (325 BCE), establishing the navigability of the corridor between India and the Persian heartland.
The Kingdom of Hormuz (c. 10th–16th century): An independent maritime kingdom controlling trade through the strait, collecting tolls from ships carrying silk, spices, pearls, horses, and cotton. At its peak, Hormuz was described by medieval travellers (including Ibn Battuta and Marco Polo) as one of the world's great trading cities.
Portuguese Conquest (1507/1515): Afonso de Albuquerque seized the island of Hormuz for Portugal in 1507 and fully consolidated control by 1515, building a fortified customs house to extract tolls via the Cartaz system — a Portuguese licensing scheme compelling all ships in the Persian Gulf to route through Portuguese customs houses or face destruction.
Anglo-Safavid Alliance and 1622 Expulsion: Portuguese control ended when Shah Abbas I of the Safavid dynasty allied with the English East India Company. The combined Anglo-Persian force besieged the Portuguese fort at Hormuz in early 1622 and captured it in April 1622, ending over a century of Portuguese dominance. Shah Abbas I (r. 1588–1629) moved the port trade to the newly built Bandar Abbas on the Iranian mainland.
British Dominance (19th–early 20th century): Britain maintained naval supremacy over the Persian Gulf and the strait from the 1820 General Treaty of Peace with the Gulf sheikhdoms until its military withdrawal from "East of Suez" in 1971.

Connection to this news: Iran's contemporary claim to sovereignty over the strait draws on historical Safavid Persian control — a claim that international maritime law (UNCLOS) explicitly rejects, since straits used for international navigation are subject to the right of transit passage regardless of territorial sovereignty.

UNCLOS and the Right of Transit Passage

The United Nations Convention on the Law of the Sea (UNCLOS), adopted in 1982 and entering into force on November 16, 1994, governs the legal regime of international straits. Under UNCLOS Part III (Articles 34–44), ships and aircraft of all states enjoy the right of transit passage through international straits — a right that coastal states cannot suspend.

Transit passage (Article 38): All ships and aircraft enjoy continuous and expeditious transit through straits used for international navigation; this right cannot be suspended even in time of war.
This is stronger than the "innocent passage" right in territorial seas (which coastal states can suspend).
The Strait of Hormuz qualifies as an international strait because it connects two parts of the high seas/EEZ and is used for international navigation (UNCLOS Article 37).
Key limitation of UNCLOS: Neither the United States nor Iran has ratified UNCLOS; however, the transit passage regime is widely regarded as reflecting customary international law, binding on all states regardless of ratification.
Iran has historically contested the UNCLOS transit passage regime and claimed rights to regulate passage through the strait based on its long coastline along the northern shore.

Connection to this news: Iran's 2026 closure of the strait and demand for toll collection are widely characterised as violations of the UNCLOS transit passage regime and customary international law, regardless of Iran's non-ratification of UNCLOS.

Choke Points and Energy Security

A maritime choke point is a narrow navigational bottleneck where a large volume of maritime trade must pass, giving the controlling power disproportionate leverage over global commerce. UPSC frequently tests choke points in the context of India's energy security, trade routes, and naval strategy.

Major global choke points: Strait of Hormuz (Persian Gulf/Indian Ocean), Strait of Malacca (Indian Ocean/South China Sea), Bab-el-Mandeb (Red Sea/Gulf of Aden), Suez Canal (Mediterranean/Red Sea), Strait of Gibraltar (Atlantic/Mediterranean), Cape of Good Hope (alternative to Suez).
India's energy exposure: India imports approximately 85% of its crude oil; a significant portion transits the Strait of Hormuz (Gulf producers — Saudi Arabia, UAE, Iraq, Kuwait).
The IEA (International Energy Agency) maintains strategic petroleum reserves (SPR) precisely to buffer against choke point disruptions; India maintains a strategic petroleum reserve with caverns at Visakhapatnam, Mangaluru, and Padur (total ~5.33 million tonnes). [Unverified current capacity]
Iran's IRGC naval forces control islands at the northern end of the strait and possess anti-ship missiles, mines, and fast-attack craft — giving it asymmetric capability to interdict far larger naval forces.

Connection to this news: The 2026 Hormuz crisis is the most significant real-world test of global energy choke point vulnerability in the modern era, directly relevant to UPSC questions on energy security, India's import dependence, and maritime strategy.

Key Facts & Data

Location: Between Persian Gulf and Gulf of Oman; Iran to the north, Oman's Musandam Peninsula to the south
Narrowest width: ~33–39 km (20–24 miles); two shipping lanes of 3.2 km each
Daily oil transit (2024): ~20 million barrels/day (~20% of global seaborne oil trade)
Share going to Asia: 84% of crude oil through the strait
China's dependence: ~1/3 of its oil imports via the strait
Hormuz Islands: 8 major islands; 7 controlled by Iran (including Abu Musa, Greater Tunb, Lesser Tunb — disputed with UAE)
Kingdom of Hormuz: Existed approximately 10th–16th centuries CE
Portuguese conquest of Hormuz: 1507/1515 (Albuquerque); Cartaz system imposed
Portuguese expulsion: 1622 (Anglo-Safavid alliance; Shah Abbas I + English East India Company)
Shah Abbas I reign: 1588–1629 (Safavid dynasty)
UNCLOS adoption: 1982; Entry into force: November 16, 1994
UNCLOS Article 38: Right of transit passage through international straits — cannot be suspended
US ratification of UNCLOS: Not ratified
Iran ratification of UNCLOS: Not ratified (but transit passage is customary international law)
2026 Hormuz crisis: Strait effectively closed since February 28, 2026; oil prices exceeded USD 100/barrel
Alternative routes: Abu Dhabi Crude Oil Pipeline (1.5 mb/d); Saudi Petroline/East-West Pipeline (5 mb/d)
India's oil import dependency: ~85% of crude oil imported
India's SPR locations: Visakhapatnam, Mangaluru, Padur
SAARC headquarters: Not relevant here — see Maldives article
Major maritime choke points: Hormuz, Malacca, Bab-el-Mandeb, Suez Canal, Gibraltar, Cape of Good Hope