Medieval Bologna Crime Mapping

Conjunction of crime and space/place has become increasingly influential. Crime Mapping. Homicides recorded in 14th-century Bologna is a pilot study focusing on Bologna, because of the richness of its State Archive, and Trevor Dean’s own previous studies using that archive, and because of the presence already of mapping technology exploited for the analysis of medieval tax records carried out by Rosa Smurra (Centro "Gina Fasoli" per la storia delle città, University of Bologna).

In the 14th century Bologna was a large city by medieval standards. It is not possible to have precise information about the number of its inhabitants: estimates vary from 50,000 to 90,000. However, areas of greater or lesser population density are known on the basis of tax records surviving since the late 13th century for the nearly one hundred parishes that, together with the four districts into which the city was divided, were the units of both administrative and religious reference.

In the years 1340-1349, 55 violent crimes were recorded in which 111 people were killed in the city of Bologna. The interactive digital maps featured here use Geographic Information Systems (GIS). Such maps are methodological toolkits to track phenomena such as the spatial distribution of crime or to identify criminal "hot spots" and socio-economic contexts.

This graduated symbol map divides the population into 5 separate classes. And each of these classes has a specific size dot depending on where the number of homicides falls into. The map shows the location of all homicides in the city prosecuted by the criminal court in the 1340s (except for a small number where the location was not specified). Homicides were clustered within the old heart of the city (within the 12th-century walls), with strong concentrations around the Mercato di mezzo (now via Rizzoli), the Piazza Ravegnana and the area towards the grain market (San Martino dell’Aposa). Also notable are the homicides on or near the routes to and from the city gates, the main entry road being the Strada San Vitale. Conspicuous is the absence of homicides in the large area to the NW of the city: this area had been included in the new wall-circuit, but was still largely undeveloped. What this shows is that homicide occurred in places of sociability, such as markets and gambling sites, and that it sought out visibility.

Visual comparison between maps showing the distribution and count of two kinds of homicides: by knife (left) and sword (right). These were the weapons most commonly used in murderous crimes.

This map shows the cases of domestic, intrafamilial homicide prosecutions. These have some specific features. First, they mainly involve men attacking their wives in their homes, though other relatives are also included, for example two men who killed their sisters, one man who killed his father, and another who killed his mother with an axe. Second, most of these killings took place inside the home, though one occurred in an alleyway (androna) and another in a portico. Third, a large proportion of these killings were committed by wounds inflicted on the throat. Lastly, the distribution across the city does not follow the general distribution of homicides: few occurred in the city centre.  

Example: December 1340: In his house, Pietro di Ventura of cappella San Felice at night assaulted his wife Filippa with a knife, inflicting many wounds to her shoulders, throat and other parts of her body, causing her death. Pietro was sentenced to decapitation and a fine of 1000 lire: Libri inquisitionum, 153 reg 5, c. 46.

Again the correlation with wealth distribution is interesting: the cappelle with more than one case of familial killing (San Leonardo and San Mamolo) were both poor districts in 1296-7 (< L 250 average estimo).

As the vast majority of homicide was committed by men and against men, it is unsurprising that the distribution of male homicide reflects the general distribution, but the particular features of intra-familial homicide (Domestic Violence map) do mean that male-on-male homicide is slightly more concentrated in the city centre, and on the streets (37 cases), porticos (34), marketplaces (3) and churchyards (sacrati: 2).

Example: June 1345, ‘Bernitius’ di Baldizone, a miller of Cappella Santa Maria Maggiore, wounded another miller, Pietro of Sant’Omobono, four wounds to his head, mouth, chest and hand, in a portico in the Cappella San Tommaso del Mercato. There were four witnesses, and he was banned in the penalty of decapitation and a fine of 1000 lire (Libri inquisitionum, 162, reg. 6, c. 54).

This map shows the parish of residence of offenders. We are using this term to encompass a variety of situations and outcomes of those prosecuted for homicide: it includes both the publicly denounced and the privately accused, and it includes both those who confessed and those who were contumacious. The vast majority of these trials (over 75%) ended with the issue of a penal ban on account of contumacy: the defendants did not appear in court to enter a defence and were convicted in absence. A small number did reach a guilty judgement with the defendant present (28 confessed and of these at least 8 were executed). Six cases were terminated by the government, and in 21 cases the offender was acquitted ,almost always because it was shown that the victim was a bandit whose killing was allowed, without penalty. One private accusation was withdrawn. Only a small group of cases (7%) had no recorded outcome.

Using the Estimi as a guide, we can see that, unsurprisingly, the more populous parishes provide more of the offenders. Parishes such as S. Dalmasio (3 hearts) or S. Agata (18 hearths) or S. Andrea (18) were home to only one offender each, while S. Leonardo (150) was home to seven and S. Isaia (296) to nine. Moreover, what is striking is that the more populous parishes were also the poorer parishes: both S. Leonardo and S. Isaia in 1296 had average household estimi of less than 200 lire, whereas S. Dalmasio average was 1200 lire. All but one of the parishes with four prosecuted offenders had average estimi of less than 200 lire. There are exceptions: some of the more populous and poorer parishes, Santa Lucia for example, produced few offenders in these years, while in equally poor and populous S. Isaia one of those accused of killing a miller in 1341 had the military-class name of Vinciguerra (‘Win-in-War’) and was the son of Niccolò Salinguerra (Accusationes, 50/A, reg. 2; Libri inquisitionum, 155, reg. 4, c. 25)

The digital maps produced to recreate the physical environment of medieval Bologna were prepared by means of topographical information obtained from the cartography of the Historical Atlas of Bologna (F. Bocchi, Atlante Storico delle città italiane. Bologna, II, Il Duecento (Bologna, 1995) and the analysis of useful sources for social and economic topography such as the Estimi di Bologna. For the mapping of violent crimes, actors and victims of crime, several features were geo-referenced, which were considered helpful for understanding the complexity of the crime phenomenon. In particular, layers were created for medieval city walls, parishes (cappelle), gambling sites (baratterie), university (studium), market areas, canals, and rivers. The map below highlights the areas of highest density of parishes.

Sources for trials

Archivio di Stato Bologna, Comune, Curia del podesta, Libri inquisitionum,

152 reg. 1 c. 136; 153 reg. 2 c. 74; 153 reg. 4 c. 55; 153 reg. 5 c. 46; 153 reg. 10 c. 84; 153 reg. 14 c. 19; 154 reg. 1 c. 24; 154 reg. 5 c. 67; 154 reg. 6 c. 39; 155 reg. 4 c. 25; 155 reg. 5 c. 116; 156 reg. 7 cc 5, 12, 14; 156bis c. 28; 157 reg. 1 c. 106; 157 reg. 4 c9 7; 157 reg. 5 c. 27; 157 reg. 6 c. 6 (and 157.1); 158 reg. 2 c. 80; 158 reg. 4 c. 19; 158 reg. 5 c. 56; 159 reg. 1 cc. 2 and 51; 159 reg. 4 c. 21; 159 reg. 6 c. 48; 160 reg. 1 c. 30; 160 reg. 2 c. 2; 160 reg. 3 c. 71; 160 reg. 5 cc. 58 and 66; 161 reg. 1 cc. 5 and 20; 161 reg. 2 c. 75; 161 reg. 3 cc, 6, 12, 43, 65; 161 reg. cc. 4 12 and 38; 161 reg. 6 cc. 69, 75, 81, 82; 162 reg. 3 cc. 14 and 16; 162 reg. 4 cc 8, 21, 26, 36; 162 reg. 6 cc. 34, 36, 54; 163 reg. 2 c. 39; 163 reg. 3 cc. 23, 35, 41; 163 reg. 4 cc 6, 11; 163 reg. 5 cc. 2 and 22; 163 reg. 6 c. 2; 163 reg. 9 cc. 18 and 23; 164 reg. 2 cc. 5, 13, 15, 36; 164 reg. 3 cc. 3, 9, 17; 164 reg.4 c. 19; 164 reg. 5 c. 29 (and 164.5); 165 reg. 2 cc. 79, 88; 165 reg. 4 cc. 15, 39, 52, 61; 165 reg. 6 cc. 37, 69, 84; 165 reg. 8 cc. 5 and 34; 166 reg. 1 cc. 6, 24; 166 reg. 3 c. 22; 166 reg. 4 cc. 2, 22, 34; 166 reg. 5 cc. 18, 34; 166 reg. 6 cc. 8, 11, 15, 26; 167 reg. 2 c. 2; 167 reg. 3 c. 57; 167 reg. 4 cc. 11, 18, 30; 167 reg. 5 cc. 10; 167 reg. 7 cc. 2, 6, 33; 168 reg. 2 cc. 22, 26, 42, 50; 168bis cc. 7 12; 169 reg. 1 cc. 11, 27; 169 reg. 3 cc. 55, 60, 64; 169 reg. 4 cc. 14, 20; 170 reg. 1 cc. 21, 40, 44, 46, 50, 58, 63. 

Comune, Governo, 272 reg. 2 cc. 6 and 73; reg. 4; reg. 5.

Accusationes: 50A cc. 2, 7, 10, 12.

Sources for demography, social and economic topography

Archivio di Stato di Bologna, Estimi del Comune, s. II, Denunce dei cittadini, buste 2-453.

Trevor Dean, Crime and Justice in Late Medieval Italy (Cambridge, 2007)

Trevor Dean, ‘Eight varieties of homicide: Bologna in the 1340s and 1440s’, in Murder in Renaissance Italy, ed. Trevor Dean and K.J.P. Lowe (Cambridge, 2017), pp. 83-106

Antonio I. Pini, 'Dalla fiscalità comunale alla fiscalità signorile: l'estimo di Bologna del 1329', in «Atti e Memorie della Deputazione di Storia Patria per le province di Romagna», n. s., XLVI (1995), pp. 344-71

Rosa Smurra, Città, cittadini e imposta diretta a Bologna alla fine del Duecento. Ricerche preliminari (Bologna, 2007)

Rosa Smurra, 'Fiscal Sources: the Estimi', in A Companion to Medieval and Renaissance Bologna, ed. Sarah Rubin Blanshei (Leiden-Boston, 2018), pp. 42-55

Massimo Vallerani, Medieval Public Justice, transl. S. Rubin Blanshei (Washington DC, 2012)