@Faye Walker, I know only a little about fine points of Latin grammar.
But I do know to disagree with
@JabbaPapa and
@Kathar1na in this realm is to butt heads with two people who really
do know what they're talking about. Double down at your own risk.
Anyway we are well off track from the original discussion.
It’s fine, but I know the difference between a syntactical set-up for a rhetorical purpose, and grammatical structure. I do not disagree that the part after the colon is the object of the verb in the phrase before the colon (I even said so upthread). However, in *no* language, not even in Latin, can you assert that, “I assert that” is an independent clause. The presence of the preposition causes the phrase to rely on whatever follows; moreover, it is almost always implied in any descriptive clause that stands on its own. For example, “The dogs in Spain are not dangerous.” In that clause, my assertion that this is so is implied. The clause itself, however, is independent.
The clause on the Compostela is complete, can stand on its own and does not rely on the introductory phrase. There is a syntactical and theoretical reliance on the verification from the implied authority (The one who makes the testimony). But that is a matter of rhetoric, not grammar.
Also, I would never just wander in to a conversation mid-stream and use a dismissive “nope” as was done to me. It was rude, aggressive, and unnecessary and earned itself a parsimoniously frank reply in what has been an otherwise fun conversation.
Edit to add: One can have two totally independent clauses thusly structured: I assert. Pilgrim X did a thing. Awkward and obtuse as that is, it does not alter the independent status of the Pilgrim X clause.
I’ll set aside matters of prepositions, a various forms of punctuation, and conjunctions for the structuring of relationships of meaning in complex sentences. I do, however, love a properly deployed semicolon.