The RaMa (Rabbi Moses Isserles, c. 1525-1572) writes of a custom to eat cheese on Chanukah. The practice, he says, is meant to remind us of the milk that Judith served to a Greek general in order to put him to sleep, thus enabling herself to put him to death. This is curious, since the book of Judith (in its present form) has nothing to do with either Chanukah or dairy products. The story takes place during the reign of Nebuchadrezzar, over 400 years before the Hasmonean revolt commemorated on Chanukah, and the heroine lulls the enemy general to sleep with wine, not milk, before decapitating him.
The version of the legend involving milk is apparently the result of a conflation of Judith's story with that of Yael (Judges 4:17-31; 5:24-28), setting us back another 600 years or so. (Yael, according to the biblical narrative, lulled a Canaanite general to sleep with a bottle of milk before driving a tent peg through his head.) The Mishna Berura (Sh"A 670) harmonizes the two as follows:
She [Judith] was the daughter of Yohanan the High Priest. There was an edict that every engaged woman should sleep with a nobleman first, and she fed the head of the oppressors cheese to make him drunk, and cut of his head, and everyone fled.
The cheese apparently made the man thirsty, causing him to drink large quantities of wine.
Most scholars date the composition of the book of Judith to the Hasmonean period, and some suggest that it should be understood as an allegory for the Jewish struggle against the Syrian-Greeks. If this is the case, the story of Judith may be related to Chanukah after all, albeit not in the manner presumed by later Jewish tradition.
This, however, is not why I try to observe the custom of eating dairy on Chanukah. I do it because it provides an opportunity to tell the story of the story of Judith, a wonderful example of the continual re-creation of history within Jewish tradition.
That, and I really like cheesecake.
*Sort of. The author seems to have thought that Nebuchadrezzar was Assyrian, so one can't take the historical setting all that seriously.