Juan Julian Merelo

History attempts to make sense of disparate information by trying to create discourse that lays a series of events with crisp cause–effect relationships in a sequence. Epochal shifts, such as the change from Antiquity to the Middle Ages, are especially complex since they involve a large number of economic, political and even religious factors which occur over long periods and that might overlap and interact through reciprocal feedback mechanisms, making this cause–effects sequence difficult to establish. In this research we adopt a data-driven and well-established methodology to identify, with quantifiable statistical precision, the moment when this shift happened, and from there arrive at its possible causes. We will use historical coin hoard data to find out whether such a shift is detected in a peripheral part of the Roman Empire, the Iberian Peninsula. To do so, we will apply different changepoint analysis methods to a time series of trade links created from that data, and conduct a retrospective analysis based on that result, analyzing the structure of the trade networks before and after the link. Thus, we progress from identifying when the shift happened to identifying where it took place, which in turn allows us to get to investigate why it happened, namely, historical events that could have caused it. This methodology can be used to analyze epochal changes in several steps using time-stamped network data, possibly finding disregarded causes or cause–effect links that could have been overlooked by qualitative methods; in this case, we have applied it to a dataset of coin hoards either found in the Iberian Peninsula or including coins minted there, finding a changepoint in the early 5th century, which, through network analysis, has been linked to a loss of trade with the area of Britannia.

History attempts to make sense of disparate information trying to create a discourse that lays a series of events with crisp cause-effect relationships in a sequence. Epochal shifts, such as the change from Antiquity to Middle Ages, are especially complex since they involve a large number of economic, political and even religious factors which occur over long periods and that might overlap and interact through reciprocal feedback mechanisms, making this cause-effects sequence difficult to establish. In this research we adopt a data-driven and well-established methodology to identify, with quantifiable statistical precision, the moment when this shift happened, and from there arrive at its possible causes. We will use historical coin hoard data to find out whether such a shift is detected in a peripheral part of the Roman Empire, the Iberian Peninsula. To do so, we will apply different changepoint analysis methods to a time series of trade links created from that data, and conduct a retrospective analysis based on that result, analyzing the structure of the trade networks before and after the link. Thus, we progress from identifying when the shift happened to identifying where it took place, which in turn allows us to get to investigate why it happened; namely, historical events that could have caused it. This methodology can be used to analyze epochal changes in several steps using time-stamped network data, possibly finding disregarded causes or cause-effect links that could have been overlooked by qualitative methods; in this case, we have applied it to a dataset of coin hoards either found in the Iberian Peninsula or including coins minted there, finding a changepoint in the early 5th century, which, through network analysis, has been linked to a loss of trade with the area of Britain.

History tries to make sense of disparate data trying to create a discourse of a sequence of events with crisp cause-effect relationships. This is specially difficult for the change of historical ages that signal an epochal shift in a specific part of the world that concerns all aspects of life, from economy to politics and religion. In this research it is fruitful to look at data and follow a well established methodology to claim when something happened and how. This is what we are doing in this paper, where we use historical coin hoard data, a proxy for economic activity and commerce, to establish when the shift from Antiquity to the Middle Ages occurred in a peripheral part of the Roman Empire, the Iberian Peninsula. We will apply different changepoint analysis methods to a time series created from that data to establish when the economic collapse that produced that change occurred, and work back from that result to actual historical events to find its proximal causes. This paper not only tries to settle that boundary, but also proposes a methodology for applying it to other sequence of historical events.

From its inception, the Republic of Venice was a state focused on maritime trade, an activity that required large amounts of capital and involved many risks. To meet these needs, the Republic used a type of contract called colleganza , a form of profit-sharing partnership by which a sedentary investor ( stans ) financed a travelling merchant ( tractor ). The colleganza benefited a large portion of the population and constituted a commercial as well as a social network. In this paper, we use an existing database of colleganza contracts to investigate access to the nobility in the Republic of Venice during the Serrata (1297–1323), a constitutional process through which membership in the Great Council, the most important political assembly of the republic, became hereditary and limited to noble families, making the patriciate the ruling class of Venice. We first show that there was no social stratification between the role of stans and tractor and that many families switched from one role to the other. Next, we investigate the probability of being admitted to the Great Council and find that it was higher for families who were more active in the colleganza , both in terms of the number of contracts and roles held, and who had higher DNSL-betweenness in the colleganza social network. We conclude that a strong presence in various roles in the colleganza contracts and centrality in the network were sources of social capital that could be harnessed to ensure the family’s social advancement and access to nobility.