CAUTION: This translator simply uses a dictionary lookup on each word to generate the Old English text. Please do not rely on it for serious translations!
Pressing shift toggles through random possible translations of the same Modern english words.
If you're looking for a translator for language like "Wherefore art thou?" then you're looking for a Shakespearean or Elizabethan translator. You can click that link to view one, but be warned, it is another "just for fun" translator and should not be used for serious work.
Translating English to Old English (sometimes called Anglo-Saxon) isn't an easy task. There are many Old English dictionaries online which can be used to simply swap out Modern English words, but this doesn't result in very accurate translations - the translations are often nonsensicle for longer phrases or sentences.
Translation engines like Google Translate rely on there being a large corpus of available literature from which to "train" their translators. Unfortunately a large corpus of Old English doesn't exist.
Hopefully at some point in the future someone may deconstruct the language and create (at least) a primitive, but accurate translator, but until then we're stuck with dictionaries. An amazing online dictionary/translator for Old English is this one. It only translates individual words, but it does it really well.