Candles became important symbols of Christianity outside chuches centuries ago when Christians were persecuted for celebrating mass.
A lit candle in a window was a secret signal that a mass was taking place.
Lights were first placed on Christmas trees in Germany in the 1500s. From there the tradition of lighted trees migrated to the UK and on to North America.
But it was not until the turn of the century - and the growing use of electricity - that fairy lights began migrating beyond the tree and windows
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