Smith, Nicholas J.C., Servicium debitum and scutage in twelfth-century England, with comparisons to the Regno of southern Italy, Thèse de doctorat soutenue en 2010, (University of Durham)
The purpose of this study is to re-assess the system of military obligation in England at the earliest time sufficient documents survive to provide an in-depth explanation. It is both an examination of the twelfth-century feudal structure and lordship arrangements as described by these documents, and how they came to be in their twelfth-century forms. This is supplemented by a similar, but briefer, evaluation of the Regno of southern Italy and of the occasional relevant documents from Normandy. An examination of the place of military obligation in the kingdom of England covers three major areas: the assessment of this obligation, the cost of service both to the king and the individual knight, and how the men actually served. These three areas offer insight into how the Normans established the servicium debitum, how knights exempted themselves from their obligation or were compensated for extra service, and various aspects of what their service entailed, such as castle guard.
A study of the returns made by tenants-in-chief in 1166 suggests that these have been misinterpreted in the past; their inspiration lay in the desire of the barons to protect themselves from excessive royal demands, rather than in the crown’s desire to update the servicium debitum. The survey conducted in the Regno earlier is unlikely to have served as a prototype for the 1166 inquiry; it was different in purpose and in form. Scutages are examined, to show the complex patterns of payment, and to suggest that under Henry II a significant number of tenants-in-chief performed their service, rather than commuted it. The Pipe Rolls are used to analyse military expenditure at a local level in two counties, Kent and Shropshire; in particular pay rates are reconstructed. A series of appendices provide details of this expenditure, along with evidence of scutages.
[Source : http://etheses.dur.ac.uk/454/]