Coleridge's famous poem "The Rime of the Ancient Mariner" has its constituent parts titled differently in different editions / online sources. For example:
Lit2Go has "Part the First", "Part the Second", and so on.
Poetry Foundation has "Part I", "Part II", and so on.
Project Gutenberg has "Part the First", "Part the Second", and so on.
Poets' Graves has "Part I", "Part II", and so on.
What is the original version here? How were the parts titled when the poem was first published?