The Charterhouse Water Maps are four illustrated manuscripts that depict the water system that was built c.1450 to provide the London Charterhouse with fresh running water.

They are also technical drawings showing a bird’s eye view of the underground system amongst ground level topographical features. These local landmarks would have been easily identifiable, enabling the pipes to be located. There are four maps in total – two dating from the medieval period when the Charterhouse was a Carthusian monastery, and two from the 17^th century when it had become a charitable foundation with an almshouse and a school.

Our research was focused on the medieval maps in particular as they are exceptional examples of early mapping in a time before maps were widely used. They are also noteworthy as the earliest known representation of a local area in London.  The monastery and its water system were situated outside the medieval City, but the area shown on the maps is today a long strip of land in the London Borough of Islington.

They also helpfully provide us with the first known depiction of the Charterhouse buildings, which gives us a clearer idea of what the monastic buildings would have looked like.  The maps are very detailed, which is unusual for early local maps.  Medieval people visualised their physical space differently to us, and so it is significant that the maps were drawn in this realistic and detailed way.

Written descriptions of land had been common place at a local level since at least the 12^th century.  They would typically record the boundaries of a person’s land, and list information about it.  Some of these written descriptions were accompanied by supplementary sketch maps.  One third of local maps made in England before 1500 originated in territorial disputes and were used to clarify legal issues.

Maps were also created for administrative purposes, illustrating land rights and water courses – the Charterhouse water maps belong to this group.  There are several surviving early maps that relate to water and the rights of access to it.  Along with the Charterhouse maps, other notable examples of early maps depicting water courses and supplies are the waterworks map of Christ Church Cathedral Priory, Canterbury (1160s), the Waltham Abbey plan of springs, pipes and cisterns (early 13^th century), and the Abingdon ‘Monks’ Map’ of the Thames (16^th century).  The closest contemporary of the first Charterhouse Water Map is a map of Chertsey Abbey and its lands (1432), held in The National Archives.

These fascinating early maps share certain characteristics.  They are annotated diagrams, designed to clearly depict infrastructure and the lay of the land.  Some of them are also illustrative, with buildings depicted in elevation with a wealth of architectural detail.  They were all made for specific purposes – to clarify issues, settle disputes, and enable maintenance.

Most early maps made for practical purposes would have been discarded once an issue was resolved, became outdated, or were otherwise no longer useful.  This means that historians have difficulty in assessing how many local maps might have existed.  It is possible that there were many more documents like them, and that the Charterhouse Water Maps are unusual because they survive.

This post is a summary of research undertaken by Sara Bortolotti and Hope Edwards.

The Charterhouse hosts week-long student placements in partnership with the Oxford University Careers Service Micro-internship programme and the Crankstart Scholarship programme, helping students gain experience of curatorial research in heritage.

Each term, we set a group of students a series of research questions relating to the Charterhouse and support them in identifying historical sources and interpreting their findings.  In return, we get a set of research reports from the students, uncovering fascinating stories from history. 

Map 1 c1450  Photo taken by The London Archives