I would only add to this: what is it that you're describing? For example, when I describe to my students the history of the Romance languages, there is a massive break between 'Latin' and 'Romance', and that this corresponds to the fall of Rome (and, say, the 3 or so centuries after that, when we have little recorded that isn't an attempt at Latin) and then the start of the feudal European states. This latter time refers to when we have written documents where the writers no longer try to emulate Latin, but the vernacular that is spoken; depending on the area you're talking about, that could be 9th-11th century.
The 'limbo' in between, well, is just that; I often call it 'purgatorio' (Dante would love me!), since we have very little in the way of written documents. We have some jarchas from Iberia, but they haven't been fully translated yet. During the Moorish conquest and occupation of Iberia, the Moors and Mozarabes (Iberians who 'converted' to the Moorish way of life), along with the Jewish Iberians, wrote songs and poetry in their Semitic languages...except the last 2 stanzas were always written in 'Romance', but with Arabic/Hebrew writing; these are the jarchas. That I know of, we don't have much else--apart from occasional 'glosses' in the margins--before the Oath of Strassburg.
So, for me, there's 3 'periods': 'antiquity' (until the fall of the Empire, or there abouts), 'limbo', and 'modern' (roughly the 9th-11th century). It's not a great division, but it's as close as I can get for my (linguistic) purposes.
This is effectively my view point: