THE PAST LOVES CHALLENGE by Gidgetgirl

In the ancient past, two canon characters were lovers. Though in this life they aren't exactly what you'd call 'made for each other,' they both start having dreams of their past life together, and one day, one of them wakes up from one such dream with a child sleeping in his/her arms, dressed in ancient garb. This child is the love child created between the two canon characters in a past life, and the child has been brought to the present to get the lovers together once more.

Some suggestions for past life:
Ancient Egypt
Ancient Greece
Something Tribal
Something more recent, i.e. Victorian

Requirements:
The child must recognize her parents by their souls, not by their physical bodies, which may or may not resemble the bodies they were in in her lifetime.

The child must have a name that corresponds to the time period of the past life, and a more modernized nickname.

A romance between two canon characters, who may or may not be likely matches for each other.

Flashbacks.

Bonus:
Someone else in the canon having lived a past life that intersected with our lovers.

A mystical explanation of what it really means to be 'soul mates' across lives.

The challenge says it all but this is set during Season 4, around the episode The Initiative. Still not familiar with one another beyond Psychology class, Buffy and Riley are both experiencing dreams of a couple from the past. This couple, as it turns out, is them in a past life. When a child is somehow brought from the past to the future they have to figure out what to do and quick. Despite not recognizing his parents physically, Kincaide recognizes them by their souls and cannot figure out why they are not together in their current lives.

You can read the fic in one long file if you prefer.