The main series of writ files of the court, arranged by return days within the four annual terms (Michaelmas, Hilary, Easter and Trinity), when the writs ordered to be returned on each of those days came into the court and were filed together. Apart from recorda files (CP 54) and the files of writs of covenant, used for levying final concords (CP 55), no other series of files of the court is known to have been created before the middle of the sixteenth century.
The filed writs were endorsed with the sheriff's account of what he had done in response to it, and returns which he had been asked to send in were sewn to the writs. They consist mainly of jury panels, lists of pledges, records of pleas in inferior courts, and occasional inquisitions. The records of inferior courts were usually taken on writs of recordare facias loquelam, and came especially from the courts of counties, but also those of hundreds and wapentakes and occasionally of manorial courts.
From 1 May 1292 the judicial writs issued by the court began to be 'signed' by the clerks who wrote them, and can be used to identify the names and numbers of clerks of the court from that date onwards. During the early 1290s the writs also gradually came to be annotated with the number of the plea roll rotulus on which the order to issue it had been recorded, and this practice was well established by 1300.
In the thirteenth and fourteenth centuries the files are arranged in a fixed county order, which then underwent some modification in the fifteenth century. The original order was: Norfolk, Suffolk, Essex, Hertfordshire, Cambridgeshire, Huntingdonshire, Middlesex, London, Kent, Surrey, Sussex, Hampshire, Wiltshire, Somerset, Dorset, Devon, Cornwall, Herefordshire, Worcestershire, Gloucestershire, Oxfordshire, Berkshire, Buckinghamshire, Bedfordshire, Northamptonshire, Rutland, Shropshire, Staffordshire, Warwickshire, Leicestershire, Nottinghamshire, Derbyshire, Lincolnshire, Yorkshire, Northumberland, Cumberland, Westmorland and Lancashire; although as a palatinate Lancaster disappeared from 1351-61 and then permanently after 1377. The fifteenth century modifications were: Norfolk, Suffolk, Cambridgeshire, Huntingdonshire, Surrey, Sussex, Essex, Hertfordshire, Middlesex ... Nottinghamshire, Derbyshire, Northumberland, Cumberland, Westmorland, and (in any order) Yorkshire, Lincolnshire and Lincoln. This arrangement means that they are readily searchable by county. Letters to the justices and warrants of attorney, sometimes very numerous, come at the beginning of some files, before Norfolk, in files for return days at the beginning of term.
The growth of business, especially at the beginning of each term, led in the early fourteenth century to the creation of two files each for the first and second return days in the term. The first part consisted of counties up to and including Gloucestershire, the second included the rest of the counties from Oxfordshire onwards. The latter files soon came to be labelled 'Oxon' on their covers to distinguish them, the first certain example of this occurring in 1322, and the first clear evidence for the existence of two files for the same return day occurs in 1316 . This practice continued for centuries.
The files available at present are those so far identified as belonging to the period from 1272 to 1387. They consist of whole intact files, part files, and small groups of individual writs found loose. Many are in poor condition and need very careful handling, and many boxes and sacks of loose materials from these and other files exist and remain to be sorted. The series continued for many centuries, and until about 1660 there are large numbers of survivors which are now boxed but remain to be firmly identified and listed..