This is an open access title distributed under the terms of the CC-BY-NC 4.0 License, which permits any non-commercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. BuddhistRoad is a project ofThis project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No 725519).Cover illustration: Official seal of the Saṁgha Overseer’s Office in Dunhuang. 10th Century.The Library of Congress Cataloging-in-Publication Data is available online at http://catalog.loc.govTypeface for the Latin, Greek, and Cyrillic scripts: “Brill”. See and download: brill.com/brill-typeface.The copyright of the Tangut Yinchuan font used in this publication resides with Prof. Jing Yongshi 景永时 of the Beifang Ethnic University (北方民族大学) in Yinchuan. For more information about this font see http://www.babelstone.co.uk/Fonts/Yinchuan.html.issn 1878-8106isbn 978-90-04-41562-1 (hardback)isbn 978-90-04-41773-1 (e-book)Copyright 2020 by the Author(s). Published by Koninklijke Brill NV, Leiden, The Netherlands.Koninklijke Brill NV incorporates the imprints Brill, Brill Hes & De Graaf, Brill Nijhoff, Brill Rodopi, Brill Sense, Hotei Publishing, mentis Verlag, Verlag Ferdinand Schöningh and Wilhelm Fink Verlag.Koninklijke Brill NV reserves the right to protect the publication against unauthorized use and to authorize dissemination by means of offprints, legitimate photocopies, microform editions, reprints, translations, and secondary information sources, such as abstracting and indexing services including databases. Requests for commercial re-use, use of parts of the publication, and/or translations must be addressed to Koninklijke Brill NV.This book is printed on acid-free paper and produced in a sustainable manner.