Engaruka is the name of an Iron Age community and agricultural complex in the eastern branch of the Great Rift Valley in Tanzania, east Africa. The site was built along the foothills of the eastern slopes of Mount Lolmalasin, an extinct volcano in the Rift Valley's Crater Highlands. Occupied between at least 1400 and the early 19th century AD, the site covers an area of almost 2,000 hectares (~5,000 acres), including stone-lined agricultural fields, terraces, houses and other structures, cattle pens, middens and irrigation canals.

Chronology

Engaruka's 500-year-long chronology has been established by a number of radiocarbon dates, combined with oral history and colonial records, as documented by Westerberg et al. 2010.

• mid-1800s, irrigation ceased
• 1855-1856, German missionaries Erhardt and Rebmann create a map marking Engaruka
• 1821-1836, Maasai capture Engaruka
• 1700s, Kisongo Maasai arrive in the rift valley
• 1620-1720, heyday of Engaruka
• 1500-1670, long distance trade declines on the Swahili coast
• 1420, drier climate change leads to construction/expansion of irrigation canals
• ~1400, Engaruka first settled

The people who built and lived on the Engaruka complex grew sorghum, and raised cattle and goats. Structures at Engaruka were built of soil, reinforced with stone and boulder cores, all within an area of approximately 28 sq km (10 sq mi).

Terrace Platforms

Most of Engaruka's agricultural fields were on gently sloping hillsides, which varied in shape and size, with step heights ranging between 30 centimeters (1 foot) to 1 m (3.2 ft) at steep locations.

The terraces often followed the natural contour of the hill slope; between them are straight stone-lined pathways, with small rectangular step-terraces on either side. A sophisticated series of canals brought water down from Mt. Lolmalasin; these are one of several precolonial irrigation systems documented in the eastern Rift Valley of Tanzania and Kenya.

• See the article on the Engaruka Irrigation System for details

At least seven distinct villages have been identified at Engaruka. The villages are made up of hundreds of residential terrace platforms elevated above the agricultural fields. These platforms measure up to 25 m (82 ft) long and 6 m (20 ft) wide, and vary in form from circular to oval to rectangular. The back edges of the terraces are supported by dry stone walling to a height of up to 2 m (6.5 ft), built to prevent the hillside from collapsing onto the terrace.

Excavating in the mid-1960s, Hamo Sassoon (1967) found midden deposits on some, but not all, of the terrace-platforms he tested up to 2 m (6.5 ft) deep, including pottery, animal bone and occasionally human burials.

Non-Residential Stone Architecture

A handful of small, strongly built oval enclosures with narrow north-facing openings were built on the hillsides. The walls of these structures are typically about 1.5 m (5 ft) high and in some cases as much as 3 m (10 ft) thick at the base. The enclosures measure 4x2 m (13x6.5 ft). Inside the structures are hearths, surrounded by seats made by arranging ten flat stones around the central hearth ring. Sassoon's (1967) excavations revealed very little occupation debris within these structures, although one with a large hearth contained iron fragments, slags and an anvil, and was likely used to forge iron, and another contained a quern used to grind cereals. Sassoon interpreted these as council houses.

At least fifty other circular structures are located in the valley below the residential zone, which vary considerably in size. A typical stone circle has an internal diameter of 9 m (30 ft), with undressed stone walls 2 m thick and 2 m high; their openings face various directions. A stone circle excavated by Sassoon included thick deposits of potsherds and animal bone: many of the pots are shape like historic pots used to make honey-beer. These structures may have been used as cattle pens.

Other Structures

About 500 cairns have been found in Engaruka, in a wide variety of shapes (circular, rectangular, triangular), and they vary up to 2 m (6.5 ft) in height with a diameter of up to 8 m (26 ft). Most of them are located on higher ground south of the main irrigation channel. At least some of the cairns contain burials, although most apparently do not. Grave goods were not found with the burials.

Finally, an extensive network of rectangular stone-lined enclosures, potentially cattle pens, covering about 200 ha (500 ac) is located in the southern part of the site.

Trade and Oral Tradition

According to Kisongo Maasai oral history, when they arrived in the area in the 1700s, they met pastoralists of Tatog origin and agriculturalists irrigating along the rift escarpment. The "Capture of Engaruka" is part of Maasai traditional history, and that event is said to have occurred between 1821-1836. Engaruka is marked on an 1856 map of the region drawn by two German missionaries, as a village along one of the caravan routes between the medieval trader Swahili culture and the inland.

Contact with the Swahili Coast traders is also in evidence from a series of glass and copper beads recovered by Sassoon; he also reported perforated ostrich egg shell disks, and some beads made of serpentine or steatite. Personal objects included several snail shell and ivory or bone pendants, ivory bracelets, worked cowrie shell, and smoking pipes made from vesicular lava. Finally, iron artifacts recovered from Sassoon's excavations at Engaruka included small iron rings, probably beads; a few leaf-shaped iron arrow points and iron awls; small stone balls are thought to be sling stones were also found. Querns and grinding pairs had carbonized sorghum grains clinging to their working surfaces.

Archaeology

The German geographer G. A. Fischer first described Engaruka in 1883; Hans Reck excavated there in 1913. Louis S.B. Leakey excavated there in 1935. Extensive excavations were conducted in the 1960s by Hamo Sassoon. Archaeological surveys of the site were conducted by J.E.G. Sutton in the 1980s; and more recently, excavations have been carried out by Peter Robertshaw, Ari Siiriainen and Vesa Laulumaa, and Daryl Stump.

Sources

This article is a part of the About.com guide to the African Iron Age, and the Dictionary of Archaeology. See page two for sources used in this article.