A single page of a medieval manuscript is full of information. Have a look at this page from Houghton Library MS Eng 701, and read about its features below.
The heading tells the reader at a glance what part of the text this is (in this case, the Prologue). It allows a reader flipping through a book to locate the part of the text that interests him or her.
A rubric is any text written in red. Here, the rubric is also the incipit of the text, which introduces the text that begins on this page and, in this case, gives the work's title ("A Pore Caytif"). Rubrics of this kind often vary from manuscript to manuscript.
The border is a decoration that delimits the boundaries of the central text area of the page. It adds visual appeal to the page.
The marginalia is a marginal note, here made by the scribe who wrote the main text, that directs the reader to a significant point in the text and sometimes, as here, provides an intertextual reference in the form of a biblical citation (Hebrews 2).
The illuminated initial also adds visual appeal to the page, and delimits a major section of the text.
The prickings are difficult to see in this image, but can be located at the far right side of the page. Prickings were added to manuscript pages after they had been cut but before they had been ruled, as a guide to uniform ruling. In this case, the book was trimmed, probably for post-medieval binding, and some of the prickings have been lost.
The rulings allowed the scribe to write evenly on the page.