Editing Codex (section)

===Structure===
The structure of a codex includes its size, format/''ordinatio''<ref name=":0" /> (its quires or gatherings),<ref name=":1" /> consisting of sheets folded a number of times, often twice- a ''bifolio'',<ref>{{cite book|last1=Gamillscheg|first1=Ernst|last2=Ševčenko|first2=Ihor|editor-last=Kazhdan|editor-first=Alexander P.|title=The Oxford Dictionary of Byzantium|publisher=[[Oxford University Press]]|year=1991|isbn=9780195046526|chapter=Quire}}</ref> sewing, [[bookbinding]], and rebinding. A quire consisted of a number of folded sheets inserting into one another- at least three, but most commonly four bifolia,<ref name="Byzantium" /> that is eight sheets and sixteen pages:<ref name=":1" /> Latin quaternio or Greek tetradion, which became a synonym for quires.<ref name="Byzantium" /> Unless an exemplar (text to be copied) was copied exactly, format differed.<ref name=":0" /> In preparation for writing codices, ruling patterns were used that determined the layout of each page. Holes were prickled with a spiked lead wheel and a circle. Ruling was then applied separately on each page or once through the top folio.<ref>{{cite book |title=The Oxford Dictionary of Byzantium |publisher=[[Oxford University Press]] |year=1991 |isbn=9780195046526 |editor-last=Kazhdan |editor-first=Alexander P. |chapter=Ruling Patterns}}</ref> Ownership markings, decorations, and [[Illuminated manuscript|illumination]] are also a part of it.<ref name="Terminology">{{cite book|last=Beal|first=Peter|title=A Dictionary of English Manuscript Terminology 1450–2000|publisher=[[Oxford University Press]]|year=2008|isbn=9780199576128|chapter=codicology}}</ref><ref name="Byzantium" /> They are specific to the [[Scriptorium|scriptoria]], or any production center, and libraries of codices.<ref name="Byzantium" />