In Roman city planning, a decumanus was an east-west-oriented road in a Roman

Ancient Rome

Ancient Rome was a thriving civilization that grew on the Italian Peninsula as early as the 8th century BC. Located along the Mediterranean Sea and centered on the city of Rome, it expanded to one of the largest empires in the ancient world....

 city, castra

Castra

The Latin word castra, with its singular castrum, was used by the ancient Romans to mean buildings or plots of land reserved to or constructed for use as a military defensive position. The word appears in both Oscan and Umbrian as well as in Latin. It may have descended from Indo-European to Italic...

 (military camp), or colonia

Colonia (Roman)

A Roman colonia was originally a Roman outpost established in conquered territory to secure it. Eventually, however, the term came to denote the highest status of Roman city.-History:...

. The main decumanus was the Decumanus Maximus, which normally connected the Porta Praetoria (in a military camp, closest to the enemy) to the Porta Decumana (away from the enemy).

This name comes from the fact that the via decumana or decimana (the tenth) separated the Tenth Cohort

Cohort (military unit)

A cohort was the basic tactical unit of a Roman legion following the reforms of Gaius Marius in 107 BC.-Legionary cohort:...

 from the Ninth in the legionary encampment, in the same way as the via quintana separated the Fifth Cohort from the Sixth.

In the middle, or groma

Groma surveying

The Groma or gruma was the principal Roman surveying instrument. It comprised a vertical staff with horizontal cross pieces mounted at right-angles on a bracket. Each cross piece had a plumb line hanging vertically at each end...

, the Decumanus Maximus crosses the perpendicular Cardo

Cardo

The cardo was a north-south oriented street in Roman cities, military camps, and coloniae. The cardo, an integral component of city planning, was lined with shops and vendors, and served as a hub of economic life. The main cardo was called cardo maximus.Most Roman cities also had a Decumanus...

 Maximus, the primary north-south road that was the usual main street. The Forum

Forum (Roman)

A forum was a public square in a Roman municipium, or any civitas, reserved primarily for the vending of goods; i.e., a marketplace, along with the buildings used for shops and the stoas used for open stalls...

 is normally located close to this intersection of the Decumanus Maximus and the Cardo Maximus.

Examples

In the ancient Roman city of Barcino

Barcino

Barcino may refer to:*Barcelona, Spain - Barcino in Latin*Barcino, Poland**Barcino...

 (present day Barcelona, Spain), the Decumanus Maximus started at the Roman gate in front of the current Plaça Nova square, which is the only Roman gate extant. In present day Croatia

Croatia

Croatia , officially the Republic of Croatia , is a unitary democratic parliamentary republic in Europe at the crossroads of the Mitteleuropa, the Balkans, and the Mediterranean. Its capital and largest city is Zagreb. The country is divided into 20 counties and the city of Zagreb. Croatia covers ...

 within the city of Split

Split (city)

Split is a Mediterranean city on the eastern shores of the Adriatic Sea, centered around the ancient Roman Palace of the Emperor Diocletian and its wide port bay. With a population of 178,192 citizens, and a metropolitan area numbering up to 467,899, Split is by far the largest Dalmatian city and...

 is the UNESCO Roman monument, Diocletian's Palace

Diocletian's Palace

Diocletian's Palace is a building in Split, Croatia, that was built by the Roman emperor Diocletian at the turn of the fourth century AD.Diocletian built the massive palace in preparation for his retirement on 1 May 305 AD. It lies in a bay on the south side of a short peninsula running out from...

. This city built by Emperor Diocletian

Diocletian

Diocletian |latinized]] upon his accession to Diocletian . c. 22 December 244  – 3 December 311), was a Roman Emperor from 284 to 305....

 exhibits the characteristic Roman orthogonal street system with the Decumanus Maximus connecting the west Silver Gate to the east Iron Gate. At the present day city of Umm Qais

Umm Qais

Umm Qais is a town in Jordan located on the site of the ruined Hellenistic-Roman city of Gadara . The town was also called Antiochia or Antiochia Semiramis and Seleucia...

, Jordan

Jordan

Jordan , officially the Hashemite Kingdom of Jordan , Al-Mamlaka al-Urduniyya al-Hashemiyya) is a kingdom on the East Bank of the River Jordan. The country borders Saudi Arabia to the east and south-east, Iraq to the north-east, Syria to the north and the West Bank and Israel to the west, sharing...

, the decumanus is extant running east-west for approximately one kilometre with its ancient flagstone

Flagstone

Flagstone, is a generic flat stone, usually used for paving slabs or walkways, patios, fences and roofing. It may be used for memorials, headstones, facades and other constructions. The name derives from Middle English flagge meaning turf, perhaps from Old Norse flaga meaning slab.Flagstone is a...

s extant; the name of this Roman city is Gadara. Another fine example is the "Straight Street", Via Recta in Damascus

Damascus

Damascus , commonly known in Syria as Al Sham , and as the City of Jasmine , is the capital and the second largest city of Syria after Aleppo, both are part of the country's 14 governorates. In addition to being one of the oldest continuously inhabited cities in the world, Damascus is a major...

, which is 1,500 metres long, connecting the eastern and western gates.

In Beirut

Beirut

Beirut is the capital and largest city of Lebanon, with a population ranging from 1 million to more than 2 million . Located on a peninsula at the midpoint of Lebanon's Mediterranean coastline, it serves as the country's largest and main seaport, and also forms the Beirut Metropolitan...

's Central Business District

Central business district

A central business district is the commercial and often geographic heart of a city. In North America this part of a city is commonly referred to as "downtown" or "city center"...

, Rue Weygand

Rue Weygand

Rue Weygand is a street in Beirut's Central Business District. Originally, the street was named Rue Nouvelle as it was a new thoroughfare constructed as part of a modernization plan in 1915...

, which runs east-west, still follows the ancient Roman

Ancient Rome

Ancient Rome was a thriving civilization that grew on the Italian Peninsula as early as the 8th century BC. Located along the Mediterranean Sea and centered on the city of Rome, it expanded to one of the largest empires in the ancient world....

, decumanus

Decumanus Maximus

In Roman city planning, a decumanus was an east-west-oriented road in a Roman city, castra , or colonia. The main decumanus was the Decumanus Maximus, which normally connected the Porta Praetoria to the Porta Decumana .This name comes from the fact that the via decumana or decimana In Roman city...