A historiated initial is an initial, an enlarged letter at the beginning of a paragraph or other section of text, that contains a picture. Strictly speaking, a historiated initial depicts an identifiable figure or a specific scene, while an inhabited initial contains figures (human or animal) that are decorative only, without forming a subject.
Source: Historiated initial – Wikipedia
Tim B.
“Letters that began a new section of a text or a particularly noteworthy section might receive more flourishes and space. They would also provide a visual point of reference, “marking the division of the text into books, chapters, paragraphs and sometimes even verses” since, due to the price of parchment, new sections did not necessarily begin on a new page.[2] “
Tim B.
https://en.wikipedia.org/wiki/Inhabited_initial
“It is similar to a historiated initial; however, the figures in historiated initials show an identifiable scene or story, while the figures in inhabited initials do not show a narrative.[1] Figures in inhabited initials may be related to the contents of the text, but do not have to be. They may be purely decorative instead.[2]”