Old English/Conjunctions

A conjunction (abbreviated here cnj.) is a type of word that connects two words, sentences, phrases or clauses together, and shows something about their relationship to each other.

There are three groups of conjunctions: coordinating conjunctions, correlative conjunctions, and subordinating conjunctions. Coordinating conjunctions join two or more items of equal importance together, like the Modern English words "and", "or", "but", and others. Correlative conjunctions are like coordinating conjunctions in that they also join two or more equal items, but they work in groups, like the Modern English words "either... or...", "neither... nor...", "both... and...", and more. Subordinating conjunctions are conjunctions that join items of unequal importance, for example Modern English "because", "although", "unless", and more.

Coordinating conjunctions
Here are some important Old English coordinating conjunctions:
 * and - and
 * ac - but
 * ne - nor
 * oþþe - or

Examples of these conjunctions in usage:
 * Hē ƿæs grēat and hēo ƿæs strang - He was big and she was strong
 * Iohannes cƿōm hraðe, ac hē ne cūðe þone yfelan hund findan - John came quickly, but he couldn't find the bad dog
 * Ƿit noldon þæt dōn, ne ƿoldon hīe - We two didn't want to do that, nor did they want to
 * Þonne þæt mōd ymbe hƿæt tƿēonode, oðþe hit hƿæs ƿilnode tō ƿitanne... - When the mind doubted that, or it wanted to know something...

Conjunctions that introduce dependent clauses
And here are some that introduce dependent clauses:
 * for þȳ þe/for þȳ/for þǣm þe/for þǣm - because
 * sƿā þæt - so that
 * þæt, þe, þætte - that (in indirect speech, like "He said that she said"; also to show desired or intended effect, as in "I desired that you would come")
 * þonne - than (used with comparative)
 * þēah (þe) - although

Examples of these conjunctions in usage:
 * Hē ƿolde cƿelan for þȳ þe hē ƿæs sƿīðe earm - He wanted to die because he was so miserable
 * Ic dyde þæt sƿā þæt þū ne ƿēpe - I did it so that you wouldn't cry
 * Þās hādas sægdon þætte þis land is heora - These people say that this land is theirs
 * Iohannes is māra þonne Æðelƿeard - John is greater than Athelward
 * Se cniht nolde feohtan þēah þe hē ƿel strang ƿæs - The youth didn't want to fight even though he was quite strong

Correlative conjunctions
Here are some that acted as correlative conjunctions:
 * ġif(... þonne....) - if(... then...)
 * ne... ne... - neither... nor...
 * oþþe... oþþe... - either... or...

Examples of these correlative conjunctions:
 * Ġif þū cume, þonne ic þec ofslēa - If you come, I'll kill you
 * Ne þæt ƿīf ne hire cild ƿǣron gladu - Neither the woman nor her child were glad
 * Oþþe hē oþþe se hund bite þisne pleġan - Either he or the dog bit this toy

Note
Note that even the most scholarly Old English writers had no qualms about writing "and" at the beginning of a sentence (Ƿulfstān did so very often in "Sermo Lupi ad Anglos") - so that is totally fine. (It also means that, in spite of some insisting that it is bad practice or bad grammar in Modern English, the practice is over a thousand years old).