Application of Kernel Density Estimates to Lead Isotope Compositions of Bronzes from Ningxia,North‐West China

The aim of this paper is to apply kernel density estimates (KDEs) to the visualization and interpretation of lead isotope data from bronze assemblages found along the northern border of central China, here designated as the Arc. New lead isotope analyses of 30 leaded tin–bronze artefacts from the Wangdahu cemetery (c.500–300 bc ) in the Ningxia Hui Autonomous Region, north‐west China, provide the basis for the discussion. By using multivariate KDEs and the calculated likelihood of the overlap, the present work shows that the Wangdahu objects feature a unique linear array of isotope ratios, representing an important element of overall bronzes from the Arc in the first millennium bc . This characteristic isotope signature is fundamentally different from that of Dajing ores in north‐east China, as well from that of early Qin bronzes in Shaanxi and Gansu provinces. This suggests that a variety of metal resources were utilized by peoples living in the Arc. The KDE approach thus proves effective at presenting and comparing lead isotope data.     

Tesserae Recycling in the Production of Medieval Blue Window Glass

The purpose of this paper is to develop a means of quantifying glass recycling and to discuss the ‘anachronistic’ chemical composition of medieval blue window glass. This method relies on a new numerical method using kernel density estimates and is based on a database of published glass chemical compositions. It seeks to reveal when, to what extent and why blue tesserae were recycled for the production of French and English blue glass. First, it is suggested that blue glass had an ‘anachronistic’ chemical composition only before the 13th century. Second, the ‘anachronistic’ chemical composition of 12th‐century blue glass comes from the recycling of both blue tesserae and non‐coloured glass. Finally, this recycling was motivated by the scarcity of cobalt sources until mines were found in the 13th century.     

Lead Isotope Analyses Revealed the Key Role of Chang'an in the Mirror Production and Distribution Network During the Han Dynasty

Chang'an (now Xi'an) was the capital of the Western Han Dynasty and the starting point of the Silk Road. In the light of the importance of Chang'an as the centre of politics, economy and cultural interaction, the overarching question proposed in this paper is focused on its role in the mirror production and distribution network during Han period. On the basis of chemical and lead isotopic analyses of 34 Han mirrors, this paper discusses the potential existence of a mirror production centre in Chang'an. Meanwhile, a comparative study with mirrors uncovered from the south‐western frontier and from Central Asian and North‐East Asian countries offers new insight into these related issues.     

Why Land Here? Ports and Harbors in Southeast Tanzania in the Early Second Millennium AD

The east African Swahili ports developed extensive maritime trading links around the Indian Ocean, and supported economic, political, and urban growth in the early second millennium AD. This article identifies ports of varying function and importance in SE Tanzania, and seeks to understand their development in the context of natural harbor advantage, boat technology, sailing practice, and resource needs. Field data from landing places are combined with weather patterns, historical documents, and oral traditions to provide an integrated survey of the ports and harbors that once sustained medieval commerce along this section of the Swahili coast. The emergence of Kilwa as an entrepôt to become the key center is based initially upon its naturally advantageous harbor facilities, safety and flexibility of approach in days of sail, and assurance of monsoon winds. Original natural advantages gradually become self-sustaining with its economic and political growth. To the north and south of Kilwa a series of ports of call with drinking water and boat servicing supported trade to and from the pre-eminent city, although some such as Kisimani Mafia and Kwale-Kisuju developed important trade functions of their own.     

From Alloy Composition to Alloying Practice: Chinese Bronzes

We propose a new methodology based on standard statistical processes for displaying and rigorously comparing the alloy composition of archaeological bronze alloys. Although traditional approaches using visual comparisons of histograms of alloying elements in an assemblage of archaeological objects are adequate for observing differences between these distributions, we argue that differences in sample size cannot be adequately accounted for without using a statistical approach. We demonstrate this methodology by comparing the alloy composition of bronzes from the sequence of Bronze Age cultures in Central China—Erlitou, Erligang (Zhengzhou, or early Shang), Anyang (late Shang) and Western Zhou. We suggest that this approach allows the identification and rigorous comparison of ‘regional alloying practices’, which in turn enables us to link the alloy composition of the objects with the intentions and skills of foundry workers.     

Panlongcheng,Zhengzhou and the Movement of Metal in Early Bronze Age China

Journal of World Prehistory - The role of Panlongcheng—a walled settlement on the Yangtze River with obvious links to the Erligang capital at Zhengzhou, ~?500 km to the...     

Shipwreck Evidence from Kilwa,Tanzania

This article reports on the artefacts and environment of marine ballast and pottery sites identified through inter‐tidal and underwater survey around Kilwa, Tanzania, one of the most important medieval sultanates along the east African coast. An inter‐tidal site on the limestone fringing reef on the approaches to Kilwa Kisiwani Harbour and an underwater site within the harbour have been dated from associated pottery to c.8th–10th century and the 13th–16th century respectively. The presence of exotic basalt ballast is discussed as an indicator of wreck‐sites.     

Interpreting Medieval Inter-tidal Features at Weelie’s Taing on Papa Westray,Orkney, NE Scotland

Investigation of the inter-tidal heritage of the Orkney Islands is used to interpret a previously perplexing complex at Weelie’s Taing on Papa Westray. The study revealed a previously unknown type of harbour since identified in several locations around Orkney. Situated in exposed environmental situations, shelter is formed by an ‘ayre’, a type of spit that encloses a loch, and which has been used historically as a landing place or crossing of the inter-tidal zone. A complex landing area, pier, tower and ship-blockage suggest Weelie’s Taing was used as a harbour. Important fishing grounds exploited since the Neolithic are nearby, and Papa Westray was the site of water-focussed religious communities. It is suggested that Weelie’s Taing was in use in the medieval period when Papa Westray was less isolated than today with the presence of ecclesiastical communities and situation on the Orkney-Shetland route.