"Proemial" is a word in ENGLISH

Suitable for an introduction or beginning; introductory; prefatory; as, an initiatory step.

Serving to introduce something else; leading to the main subject or business; preliminary; prefatory; as, introductory proceedings; an introductory discourse.

Pertaining to, or of the nature of, a preface; introductory to a book, essay, or discourse; as, prefatory remarks.

Introductory; previous; preceding the main discourse or business; prefatory; as, preliminary observations to a discourse or book; preliminary articles to …

Of the nature of a prolegomenon; preliminary; introductory; prefatory.