# Silver Isotopes in Silver Suggest Phoenician Innovation in Metal Production
## 1 Introduction  
For millennia, lead ores were mined to produce silver. The mining process included identifying potential areas for exploitation, the prospection of vertical shafts to provide access to veins of lead-rich minerals (the lead ore). Then, horizontal shafts that followed the direction of the vein were excavated [1, 2]. Silver (Ag) was extracted from the lead ores by a two-step process: first smelting the ore in a furnace, instigating the reduction in the ore into metallic Pb-Ag, followed by cupellation, namely, oxidizing the alloy in a cupel for extracting Ag (and gold) and separating it from other metals. This technique, practiced from the 4 th millennium BCE [3, 4], enabled the extraction of silver from angentiferous galena (PbS) and creussite (PbCO\({}_{3}\)) lead ores [5]. The quest for metals, especially silver, was a crucial instigator of Phoenician early endeavors to the West Mediterranean at 950-800 BCE [6]. The Phoenician city-states in Lebanon and the northern shores of the southern Levant during the Iron Age (11 th-6 th centuries BCE), e.g., Tyre, Sidon and Bylos, 'Akko and Dor' (for part of this period), shared political-economic traits and material culture (Figure 1; e.g., [7, 8, 9, 10, 11, 12, 13, 14]). The Phoenicians are known for spreading to Europe long-lasting innovations, including the alphabet, murex-based purple dyeing and masterful craftsmanship (e.g., [7, 15]). However, above all, thePhoenicians are renowned for their seafaring prowess and far-flung trade, establishing colonies in North Africa, Sardinia and Iberia (e.g., [8; 16; 17; 18]). Yet the Phoenicians were not mere traders. In the 9 th century BCE, the Phoenicians extracted silver from jarosite ores in Iberia. They innovatively added external Pb from nearby ores to the Ag-rich jarosites to produce silver (see more below). The basic silver-production process, which was based on cupellation, did not change and also remained in use throughout the Classical periods (e.g., [19; 20]). As all cupelled silver contained Pb, lead isotopic analysis (LIA) has become the prevailing sourcing method for ancient silver. This method directly compares the Pb isotopic ratios of ores with those measured in archaeological artifacts (e.g., [21]). The chemical composition of the silver is less useful for provenance since most of the elements are either largely removed during production or their concentrations depend on the quality of the cupellation process [6; 22]. A few elements (Pb, Au and Bi) can sometimes be used in order to identify idiosyncrasies resulting from the use of different ores [6; 22; 23; 24; 25; 26]. Silver in the Near East was an important commodity and means of currency long before the invention of coinage (e.g., [27; 28; 29; 25]). More than 40 silver hoards unearthed in the Southern Levant, remnants of 1400 years (\(\sim\)2000-600 BCE) during which silver was a central means of exchange in the region, form a large and accessible database (Figure 2; [27; 28]). Based on Pb isotopic and chemical analyses of 250 items from 22 silver hoards, we identified the sources of silver in these hoards throughout the Bronze and Iron Ages [6; 26; 30; 31]. We showed that during this long period, the sources of silver changed over time. In the Middle Bronze Age (\(\sim\)2000-1550 BCE), silver was brought to the Levant from Anatolia and the  
Figure 1: Map of the Southern Levant showing sites with Bronze and Iron Age silver hoards. (Drawing by [PERSON]; Reproduced after [25]). Aegean [26]. During most of the Late Bronze Age (~1550-1250 BCE), gold probably replaced silver as the main currency, with some silver from Laurion, Greece, being used at the end of this period [26]. Following the Late Bronze Age collapse, throughout the Early Iron Age (~1200-950 BCE), silver was scarce and often mixed with Pb-rich copper. This affected the Pb isotopic composition of the silver items, and thus the origin of the silver has remained largely unknown [30]. The Phoenicians revived the trade-in silver in the mid-10 th century BCE.