Proc Soc Antiq Scot, 121 (1991), 181-214 The Atlantic Scottish Iron Age: five levels of chronology lan Armit* ABSTRACT Five forms datingof evidence currentlyare relevant archaeologythe to Atlanticthe of Scottish Iron Age. These defined evaluatedare and constructto sequencea structuralof and artefactual development. arguedItis that lacka of evaluationclaritythe on datingof methodsis responsible currentmuchfor the of confusion literature.the in Alternative chronologies thatto constructed here valid, mustare but explicit be theiron evaluation dating ofthe evidenceon and the weighting primacyand datingof levels. The terminology of the 'atlantic roundhouse' is introduced as a framework which enables conventional structural typologies morebe to effectively analysed. Within extendedthe chronology terminology usingnew and the descriptivea as device, developments tracedbe can which perspectives offernew settlementthe on sequenceand undermine the unilinear models of the Atlantic Scottish Iron Age. Differences in development between the Northern and Western Isles are already becoming apparent. CONTENTS Introduction ................................................2 18 . Five level datinf so g ............................................3 18 . Level 1: C14 dating ............................................. 184 Patterns in the C14 data ...................................... 184 800-400 BC ..............................................7 18 . 400-200 BC ..............................................9 18 . 200 BC-AD 100 ............................................. 190 Level 2: The quern transition ....................................... 190 Northern quern evidence ....................................2 19 . Western quern evidence ...................................... 194 Leve : Romal3 n material ........................................6 19 . Level 4: Native material culture ..................................... 198 Native pottery ............................................. 198 Metalwork ..............................................0 20 . Glass .................................................. 200 Level 5: Structural typology ....................................... 200 Summary sequence ............................................. 201 Discussion .................................................2 20 . * Centr r Fielefo d Archaeology, Universit f Edinburgyo h 182 | SOCIETY OF ANTIQUARIES OF SCOTLAND, 1991 INTRODUCTION Atlantie Th c Scottis histora s h ha investigatio f Iroye o nAg n stretching mid-19t e bacth o kt h century when early Scottish antiquaries first became fascinated by the brochs, among the most visually strikin f lateo g r prehistoric monument n Britaini s s wity sucA . an hh impressive monument type the brochs and associated structures were subject to considerable early, albeit inadequate, excavation, producing structural and artefactual information which, while large in quantity, is often deficient in quality. Roman period artefacts were noted in early work as being of relatively well-known chronology and their occurrence on broch sites was taken to indicate a Roman period floruit of broch architecture. The concept of multi-periodicity was very poorly developed mid-20te prioth o rt h centur eved yan n some later excavator Atlantin si c Scotlands a , Cuien Du rt a (Young 1956, reinterprete Armin di t 1988a), apparently faile distinguiso t d h relatively clear structural phases. The dating of structures was based on comparisons of artefactual material with what were though better-understooe b o tt d region southern si n England and elsewhere. Diffusion fro soute mprocessassumee s th th h wa e whicb y b o d distinctivt e hth e Scottish material and structural assemblages came into being. The history of interpretation has been haunted by a number of preoccupations which have their root n antiquarianismi s e obsessioth : n wite originath h l heigh f brochso t e th , overriding concern wit e detaihth f architecturao l l typologe vieth w d thayan t brochs were outwith the day-to-day settlement patterns of the period, all have their origins in the 19th century. Childe's term, 'Castle Complex', coinesmale th f coveo ldt o drystonl al r e round- houses of the Atlantic Province, unwittingly sustained the emotive and subjective approach to subjece th t (Childe 1935). Childe' sAtlantie worth t kse c Scottis contexe th a n h i f Iroo e t nAg wider diffusionist scheme, linked to historical events in the south of England. His ideas were subsequently refined, most notably by MacKie who attempted to trace the broch builders back to the refugees from Caesar's rout of the Veneti in 56 BC (MacKie 1983, 120). Chronology has often been dictated by these interpretations. Despite much dissatisfaction wit detailee hth d theorie brocf so h origin 1960e th d f san o 1970s, the diffusionist views have proved resilient to change and the field has remained substantially unaffected by new approaches to archaeological problems elsewhere. This paper doe t see sno reinterpreo kt Atlantie th t c Scottish Iron Age: instea wilt d i restrictee b l e th o dt dating evidence. This data is incompatible with the diffusionist views of the 1960s and 1970s and requires instead the adoption of approaches which deal with the evidence in terms of indigenous development (albeit with contacts in several spheres of material culture with areas to the south). e terminologTh y used her o describt e e drystonth e e structure f Atlantio s c Scotland requires some explanation. The term broch has attracted such a wealth of associations and subconscious prejudices tha s usefulnesit t n archaeologicaa s a s l ter s mopei o questiot n n (Armit 1988a) n thiI . s paper broch architecture wile employeb l a collectiv s a d e term encompassin granga structuraf eo l traits froundrystone th n di e structure Atlantie th f so c Iron e (ArmiAg t 1990a) s meani a usefut i ;s a t l shorthand form referrin e techniquth o t g f o e hollow-wall construction and the use of such traits as scarcements, intra-mural stairs, guard-cells etc. The thick-walled drystone roundhouses of the Atlantic Iron Age will be termed atlantic roundhouses', this term covers all those related structures previously subdi- vided into brochs, duns, galleried dun t includinsno etct bu , g structures where elementf so broch architecture are used outwith the domestic sphere, for example promontory forts, blockhouse r Harding'so enclosuren sdu s (Harding 1984). ARMIT: THE ATLANTIC SCOTTISH IRON AGE: FIVE LEVELS OF CHRONOLOGY 183 Individual structures will be classed as simple or complex atlantic roundhouses; the simple atlantic roundhouses are those which, although they may be massively built, lack evidence for the use of the specific traits of broch architecture; the complex atlantic roundhouses emplo f theso y l someal traitr o e n theii s r constructio d includan n e those structures previously classe s brocha d towers. This latter term wile useb l o describt d e structures with palpable evidence of multi-storey construction (MacKie's brochs (1983)) but does not imply a typological distinction; conditions of survival are such that it is virtually impossible to separate a class of broch towers from other types of complex roundhouse in the field. Further discussion of this new terminology has been published elsewhere (Armit 1990a). The simple roundhouses encompass structures recently excavated in the north eg Tofts Ness , PierowalBu , l etc s wellarga a ,s a le rang f westereo n structures previously classes da duns e complexTh . roundhouses encompas galleriee sth d wes e more dun th wels th a f t s seo a l familiar brochs. Wheelhouses remain a separate phenomenon in terms of the terminology, reflecting their different architecture (Armit 1990b). FIVE LEVELS OF DATING Five different types of dating evidence will be considered: the body of C14 dates available from relatively recent excavations; the evidence of quern types; cross-dating using Roman material; native material culture; and structural typology. Having defined these forms of chronological evidence it is necessary to consider the weight to place on each: a hierarchy of dating method e createb n ca sd placing these type f evidenco s n descendino e g levelf o s reliability. In this pape argues i t i revidenc 4 dC1 thae th te shoul startine takee db th s na g poinr fo t analysis assumptione Th . whicn so methoe hth d rest basee sar d outsid reale eth Atlantif mo c Scotlan afford dan chanca d value shako et th f e eof label s which have become associated with various structural forms through a century of typological schematizing. The second level of dating will be the evidence of quern types; the full evidence for chronological significance of quern typology is discussed below but in essence it is a relatively uncomplicated chronological indicator which, if one takes the premise of a 'quern transition', is not subject to multiple interpretations. e thirTh d leve f chronologicao l l evidence, tha f Roman-deriveo t d material s mori , e difficul deao t t l with, principally becaus generalle th f eo y poor recordin sitee whicth n so f go h it has been most often found. Although the meaning of Roman associated material within native Scottish context fror fa ms si clea stils i t li r perhap morsa e reliable chronological guide than the native material culture which has resisted many attempts at typological and chronological ordering. This fourth leve f datino l g base nativn do e material culture wile b l discussed more fully below. The final level of dating to be considered