Northmen

[Guinevere]

These Northmen were in fact the ancestors of the Rohirrim !
After the invasion of the Wainriders and the wars which involved Gondor and their allies, the Northmen, for nearly 100 years, some of them fled to Dale and merged with the people there, some took refuge in Gondor, and the rest (under Marhwini, a descendant of Vidugavia) passed north and settled in the Vales of Anduin. This was the beginning of the Éothéod.

This is stated in Unfinished Tales "Cirion and Eorl"

In the Notes to that Chapter, Christopher Tolkien writes about the origin of their names:

It is an interesting fact (...) that the names of the early kings and princes of the Northmen and the Éothéod are Gothic in form, not Old English (Anglo-Saxon) as in the case of Léod, Éorl, and the later Rohirrim. Vidugavia is latinized in spelling representing Gothic Widugauja (wood-dweller) , a recorded Gothic name, and similarly Vidumavi Gothic Widumawi (Woodmaiden). Marhwini and Marhari contain the Gothic word marh (horse), corresponding to Old English mearh plural mearasthe word used in LotR for the horses of Rohan.(.........)

Since, as is explained in Appendix F (II), the language of Rohan was "made to resemble ancient English" the names of the ancestors of the Rohirrim are cast into the forms of the earliest recorded Germanic language.

I hope this answers you question, Elianna. As you see, you were right with your guess about the Goths! However, its not the people, only the languages that Tolkien took for a model!