In 1066, the Norman Conquest of England took place under the leadership of William the Conquerer. The Normans were French and French is a "Romance" language; that is, it is from the "Roman" or Latin. English is a Germanic language. Thus, English and French are from two different branches of the Indo-European language family. If you research "language family charts" you can see this visually. Latin, and all of its sub-languages, is from the "Italic" section. French comes under this heading. English is from the "Germanic" section.
When the Norman French took over, Old English was spoken in England -- different than German, but similar in spelling, grammar (there were three genders - masculine, feminine and neuter), sound and vocabulary. It was a much more gutteral sounding language than English is today. Under the Normans, French became the language of government and of the ruling class, so the English lords and even the common people had to learn a bit of French. Likewise, the French had to learn a bit of English in order to govern the people they had conquered. Plus, over time, the Normans intermarried with the English. Gradually, vocabulary came into the English language from the French through "borrowing" (which is one of the processes through which languages acquire words - coinage, borrowing, compounding, blending, clipping, backformation, conversion, acronyms, derivation, prefixes and suffixes, infixes etc.).
English went from what we call "Old English" which is closer to the Germanic to "Middle English" which is a blend of "Old English", Norman French, Latin and other influences. The neuter gender all but disappeared from English - the only place where we now have "neuter" is in the genderless pronoun "it" and "one" - "it will have to suffice" or "one can see that this is complicated." The spelling of Old English is very different than Middle English. Here is the Lord's prayer in Old English:
Fæder ure þu þe eart on heofonum;Si þin nama gehalgod,to becume þin rice,gewurþe ðin willa,on eorðan swa swa on heofonum
Here it is in Middle English:
Oure fadir that art in heuenes, halewid be thi name; thi kyndoom come to; be thi wille don in erthe as in heuene:
English did not borrow the Latinized gender that the modern Romance languages have today - if you speak a foreign language, you have probably struggled memorizing which nouns are masculine and which are feminine, and when you modify them, the adjectives must also agree in number (singular, plural) and gender (masculine, feminine, neuter) with the noun being modified -- "¡Que lástima!" (Spanish) and "quelle horreur!" (French).
If you check out the links below, there is more specific information - this is just an overview - and do research the language family chart - it's very interesting to see. Perhaps you are already familiar with the language family chart for Indo-European, since you are in grad school.