Indoor Herbs Losing Leaves in December

I have some herbs I planted in oblong clay pots in the summer: lemon verbena, basil, oregano, rosemary, parsley, Spanish lavender and mint. Throughout the summer they flourished marvelously and became quite large and healthy. In fact, they have been lovely until recently. In late September I brought them in their oblongs pots, indoors, intending to continue having fresh herbs over the winter. I put them on shelves near a sliding glass door where they get fall and winter light. The problem is that now, in December, they are suddenly dropping their leaves--which are dry and crunchy--and leaving the stems bare and woody. Is this normal? Do herbs die-off or die-back in the winter EVEN IF BROUGHT INDOORS? Or are my herbs likely dying, period? I would appreciate your advice for I have lost three times now Spanish lavender that had grown beautifully large, very large, over 8-10 months and then suddenly dried-up, dropped its lush leaves and "died".

All of the herbs you mentioned need to be kept in a very sunny window to do well over the winter. Check our web-site <www.richters.com> at "Q&A", "Search Question and Answer" type in "Bringing Indoors" or "overwintering indoors" to get other hints on the subject.
The lemon verbena is deciduous and will drop its leaves and remain bare for a month or two before sprouting new leaves.
Basil is an annual and will continue for a while, but eventually it is going to decide that its time to die.
Greek and wild oregano and mint die down out of doors but as long as they are kept cool, they don't die down indoors. Perhaps you kept them too hot and dry?
Rosemary would only die or drop all of its leaves if you allowed the pot to dry it out completely at some point.
Parsley should be kept moist and a bit on the cool side, but out of frost. Frost makes it bolt to seed and after that it dies.
Spanish lavender should be kept cooler in the winter but still bright and moist.