This publication in the series Oxford Studies on the Roman Economy is focused on capital and innovation and is wedded to a neo-institutionalist approach. It is the latest publication from the research group ‘Factors of Production in the Roman World’, which has already produced two volumes, Ownership and Exploitations of Land and Natural Resources in the Roman World in 2015 (edited by Erdkamp, Verboven and Zuiderhoek, published in the same series) and Work, Labour, and Professions in the Roman World in 2017 (edited by Verboven and C. Laes).

In their introduction the editors clearly state what they hope to examine within this volume, namely how the Romans produced, used, assigned and stored resources required to manufacture goods and deliver services; what the impact of Roman institutions and views on these activities were; whether capital and investment were acquired through market mechanisms or via other channels; whether access to these resources for production improved over time; and whether it had a positive effect on goods and services. They clarify some of the key terms used: ‘capital’ and ‘capital goods’ are defined as (a) ‘financial assets that can be used to invest in the production of goods and services’ and (b) ‘durable man-made goods used as inputs to produce further goods or services’, respectively (p. 5); for ‘capital’ one may therefore read ‘investment’. They further set out the pitfalls in applying modern terminology to the Roman economy, especially when it comes to differentiating between status expenditure and ‘economic’ investments (p. 7). Even so, the editors are keen to explore investment attitudes and behaviour (i.e. taking economic risks), and they discuss the previously rather limited scholarly discourse on this issue. They furthermore declare their interest in investment objectives such as maintaining, consolidating and increasing wealth; in acquiring financial assets and the functioning of credit markets (loans); in investment opportunities such as public contracts and public capital goods (e.g. land and quarries); and in the institutional framework of investment. Somewhat distinct but not easily separated from investment and capital goods is innovation, that is, the use of technological progress and inventions to improve the quality and quantity of products and the efficiency of the production process. They also understand innovation to include the organisational streamlining of production without recourse to technological advances.

The agenda for the volume as set by the editors is ambitious, and most chapters contribute successfully towards the goal set. The chapters are divided into three parts: ‘Investment and Innovation’, ‘Capital and Investment in the Rural Economy’ and ‘Human Capital, Financial Capital, and Credit Markets’.

In the first chapter of Part 1, ‘Population, Technology, and Economic Growth in the Roman World’, Erdkamp offers a discussion of the theoretical models he discerns as being most useful in explaining archaeological evidence for increased growth. Most intriguingly he instrumentalises recent theoretical debate on technological innovation as a product of population size and density to argue that the expanse of the Roman Empire together with increased communication and mobility also drove the spread of innovations and ideas; the mere size of the urbanised empire thus promoted technological innovation. These were not new inventions necessarily but often improvements on existing technology. C. Vigiletti's ‘Innovations and Uses of Wealth in Archaic Rome and Latium (Late Eighth to Early Fourth Century bc)’ pushes for a more dynamic view of the economy of Archaic Rome rather than the static conservative economy it was hitherto claimed to have been. Based on his analysis of the archaeological evidence he argues that Rome and Latium were open to selecting and adopting innovations in farming and improvements to industrial and building techniques. W. Broekaert and Zuiderhoek take a closer look at investment in ‘Capital Goods in the Roman Economy’; they direct their attention towards three case studies: (1) agricultural tools, equipment and workspace; (2) capital goods in riverine and maritime transport; and (3) tools and workspaces in urban production. The case studies are intended to provide answers as to who the investors were and if producers/labourers had control over these ‘means of production’; who made these capital goods; and how their distribution was organised. What emerges clearly from their analysis is a reliance on the wealth of city councillors, knights, senators or rich freedmen and magistrates of collegia, all in all a minor part of the population. The possibility, however, that others might have pooled their resources to acquire capital goods cannot be excluded. The producers of goods, Broekaert and Zuiderhoek argue, could gain access to these capital goods either as part of an elite household (familia) or through leasehold, which also rested on pre-existing social connections. In ‘Roman Water Power: Chronological Trends and Geographical Spread’ A. Wilson draws together the evidence for the use of water power across the empire and shows that grain milling powered by water was well established by the first century ce and that water-powered ore crushing came into existence around the same time. By the second century ce water was used for sawing timber and by the third century for stone. He therefore can debunk the long-held narrative of waterpower only really coming into use during the medieval period. N. Monteix, in ‘The Archaeological Perception of Capital and its Transformation in Urban Occupations’, examines capital goods in urban contexts, that is, the prospects of gaining insight on central questions of investment and innovation through analysing the archaeological evidence.

The second part is concerned with ‘Capital and Investment in the Rural Economy’. M. Ronin, in ‘Funding Irrigation: Between Individual and Collective Investments’, is interested in capital investment in irrigation systems. She focuses, in part, on legal institutions such as servitude rights in guaranteeing access for individual landholders to water; and she highlights the role of urban aqueducts in supplying water to rural estates (A. Willi's Irrigation in Roman Western Europe [2021] was not yet available to Ronin). M. Stringer, in ‘Impensae, operae, and the pastio villatica: the Evaluation of New Venture Investments in the Roman Agricultural Treatises’, addresses the question whether the surviving agricultural treatises allow us to glimpse at the principles deciding the allocation of resources to different schemes generating income, for example, crops, stock-rearing, quarrying etc. Although he undertakes a detailed linguistic analysis of key terms such as sumptus or reditus in Cato, Varro and Columella, only Columella really seems to reveal an understanding of a cash return on investment, especially in the context of vineyards or pasturing (pastio); the production of crops or olive oil was less subjected to an analysis of investment costs and returns. The available evidence seems not to offer proof for a systematic approach to investment decisions. In ‘A Story of Land and Water: Control, Capital, and Investment in Large-Scale Fishing and Fish-Salting Operations’ A. Marzano explores the factors defining the exploitation of fishing grounds in coastal lagoons and the sea. Due to the ambiguous legal status of lagoons, local communities could get into conflict with the publicani over who had the right to lease out their exploitation. Marzano makes the case that members of different segments of Roman society, from freedmen to the upper strata, invested capital in this sector, in the case of the less wealthy often in partnerships procuring fishing boats, nets and other equipment. T. Lewit, in ‘Invention, Tinkering, or Transfer? Innovation in Oil and Wine Presses in the Roman Empire’, does away with the dominant narrative on the adaptation of the screw to oil and wine presses, which rests solely on the literary sources of Cato, Pliny and Hero. She demonstrates that the distribution of different types of press also showed geographical rather than just chronological variation. In explaining the observed variations, Lewit factors in the desire to increase return on investment, local landholding and production patterns, as well as safety concerns.

Part 3 is concerned with ‘Human Capital, Financial Capital, and Credit Markets’. N. Underwood, in ‘Labouring for God: the Clergy and Human Capital in the Later Roman Empire’, ventures beyond the scope of the Roman Republic and Principate by looking at the recruitment of the clergy between 360 and 540 ce. Legal limitations required the Church to focus on urban professionals and merchants. This pool of human resources allowed the Church to expand its economic activities. ‘Capital Markets and Financial Entrepreneurs in the Roman World’ by Verboven focuses specifically on the organisation of financial services provided by deposit bankers, brokers and other mediators, and surveys the varying financial instruments to fund investments. How efficient these credit markets worked is difficult to establish: lenders might have had some difficulties recuperating monies from debtors beyond their immediate reach through legal means; and the size of the credit market is difficult to establish. To what extent credit was used to finance capital goods remains beyond the reach of our sources. J. Andreau, in ‘Capital and Investment in the Campanian Tablets’, revisits the tablets of L. Caecilius Iucundus, the Sulpicii and Poppea Note and takes a closer look at the ways by which freedmen may have successfully amassed capital (e.g. lending money with interest, direct investments). M. Haklai's contribution, ‘Credit and Financial Capital in Roman Egypt’, is concerned with the issue of whether the documentary papyri provide evidence of interest-bearing deposits, i.e. the use of παραθήκη agreements for both interest-bearing loans and deposits, and whether such a shift facilitated economic transactions. Lastly, L. Gregoratti, in ‘Temples and Traders in Palmyra’, attempts to identify the temples in Palmyra as banks where private monies were deposited and could be used to fund further trade enterprises. His hypothesis rests on circumstantial evidence, especially the close link of caravan-trading families with the Temple of Bel and smaller sanctuaries at Palmyra. A succinct and useful index completes the volume.

The varied contributions offer different methodological approaches in answering the important questions that Erdkamp, Verboven and Zuiderhoek raise. As usual with edited volumes of this size, cogent answers do not necessarily emerge, but the debate is enriched by the detailed analysis of the evidence. What needs to be lauded is the rich conspectus bringing archaeological, documentary and literary evidence together. Given the relative size of the book, one wonders whether perhaps the themes of capital goods and innovation might have merited a second distinct volume. Overall, the editors present us with excellent studies and an important starting point for further explorations into capital goods and investment in the Roman world.