As for where the ceremony came from, the origins of the unity candle are still a little hard to peg down. So far, I have rounded up three versions regarding to the unity candle ceremony. Find dresses in 100 colors at UWDress.com.

The first version is that: Sometime in the last 50 years or so in America it began to spread, igniting a trend that was quickly adopted by many Christian marriages. Catholicism is generally not included, because the ceremony is not included in the wedding mass, and thus would not be sanctified by the church.

Some people lay the origins of the ceremony at the feet of the candle companies themselves, similar to the greeting card influence on lesser holidays like Valentine's Day. It's more likely that 30 or 40 years ago, a small tradition began to pop up in Protestant weddings of lighting a unity candle, the candle companies saw their business opportunities, began to sell the unity candles, only causing it to spread.

The third version attributes the unity candle ceremony to the conceptual symbolism, rather than out of historic ritual. For example, the concepts that Jesus is the Light and that we are to let our lights shine before men in order to reflect God’s glory and make the use of flames a poetic depiction of two Christian lives becoming one.  Once the two flames merge and create a new flame, there is no way to then separate out the two individual flames. They are inextricably one.

God appeared to Moses in a burning bush.  Moses turned aside and looked at this great sight.  Lighting the unity candles, with the understanding that the joining of two into one is the work of the same God who appeared in fire on the bush and in the pillar and to whom darkness is as light, gives opportunity for the bride and groom, and for all the guests, to marvel at the work that God has done in this covenant marriage. 

No matter how this tradition started, it's the TV serials General Hospital in 1981 performed this ceremony, which probably brought sizable attention to it for those that had never witnessed or heard of the unity candle.