The project Estoria Digital was funded by a generous grant from the Arts and Humanities Research Council: Dr. Aengus Ward, An electronic research environment and edition of the Estoria de Espanna of Alfonso X, King of Castile and León, AH/K000136/1, 2013-16, £559,267 and the Impact tools were developed as a result of AHRC award Dr. Aengus Ward, Alfonso el Sabio and the Estoria de Espanna: the past in the digital present, AH/N006658/1, 2016, £99,853. We would like to express our gratitude to the research council for the grant, without which such a large scale and ambitious project could not have been undertaken.

We would like to acknowledge the help and advice offered by a range of colleagues, some of whom must remain anonymous but whose comments improved immeasurably the project. In particular Dr. Bárbara Bordalejo was a font of invaluable support in the drafting phase and had sole responsibility for the vital technical apparatus. Katharina Freise and Sheena Robertson gave their time and expertise beyond the call of duty in the application phase, as did Emily Hargreaves for the Impact application. Debbie Jones and Afroze Zaidi-Jivraj also provided invaluable support.

We would like to acknowledge the generous support of a range of libraries and archives which facilitated our access to the manuscripts of the Estoria de Espanna. These are: Real Biblioteca del Monasterio de El Escorial, and in particular to José Luis del Valle Merino whose knowledge of the collections and enthusiasm for research is unmatched; the Biblioteca Nacional de España, and in particular to Carlos Alberdi, Gema Hernández Carralón, Mercedes Pasalodos Salgado, Pilar Egoscozábal and especially Cristina Guillén Bermejo from the Sala Cervantes; the Biblioteca de Menéndez Pelayo and its wonderful directors Rosa Fernández Lera and Andrés del Rey Sayagués; the Biblioteca de San Eloy and its director José Antonio López González who aided us in our quest for manuscript Ss; the Biblioteca General Histórica de la Universidad de Salamanca and its director Margarita Becedas-González and the James Ford Bell library at the University of Minnesota, and its curator Marguerite Ragnow. We owe a special debt of thanks to the staff of the Instituto del Patrimonio Cultural de España in Madrid for their restoration of manuscript T: Ana Ros, restorers Pilar Díaz Boj and Maria Sánchez Dominguez and the expert on binding Isabel Lozano de Gregori and also Laura Fernández, Vicedecana de Investigación, Relaciones Institucionales y Relaciones Internacionales de la Facultad de Geografía e Historia de la Universidad Complutense de Madrid.

We would also like to thank the librarians and staff at the central library and Cadbury Library of the University of Birmingham.

We owe an especial debt of gratitude to our Advisory Board of Professor Leonardo Funes, Dr. Francisco Bautista, Dr. Juan Carlos Conde López, Dr. Manolo Hijano Villegas, Dr. Virginie Dumanoir, and Dr. Geraldine Hazbun for their advice and help in access to archives.

Francisco Bautista was of particular help in all matters relating to manuscript Ss and in facilitating our negotiations with the Universidad de Salamanca. Juan Carlos Conde was instrumental in organising our colloquium at Magdalen College Oxford in November 2014.

Our colloquium in Sevilla could not have taken place without the untiring help of Blanca Garrido Martín and Javier González Gómez and the goodwill of Lola Pons.

Thanks also go to Georges Martin and Hélène Theulin Pardo (Paris Sorbonne), Marta López Izquierdo (Paris 8), Leonardo Funes (Buenos Aires), Amaia Arizaleta (Toulouse), Barry Taylor (British Library and AHGBI in Galway), Albert Lloret (IMC Kalamazoo), Emily Francomano (Georgetown), Francisco Bautista (Salamanca), Michelle Hamilton (Minnesota) and Rosa Vidal Doval and Rachel Scott (Queen Mary) for invitations to present details of the project as it evolved and as a result of which the edition will be much improved.

We would also like to recognise an enormous debt of gratitude to Inés Fernández-Ordóñez for her incomparable wisdom on the subject of the Estoria de Espanna and much more; but also for her help in our negotiations with Patrimonio Nacional. In the same vein, we would like to thank Rosa Rodríguez Porto, Pedro Sánchez-Prieto Borja and Alberto Montaner for their generosity and advice.