I'd never heard this until my SiL told me about it this past weekend:

legend of the tabby cat

Author Unknown

And so it came to pass that a husband and wife journeyed to a small town called Bethlehem, as the king had decreed that all the people stand to be counted in the small towns and teeming cities from whence they came. The journey was long and hard for both, but especially for the young wife, who was very near to bringing her firstborn son into the world.

When they at last reached the crowded and noisy town, the expectant father searched hurriedly for a place for them to rest and where the child could safely be born. But at every door, he was told there was no available room. Finally, an old inkeeper, though having no space left in his inn, took pity on them and offered them shelter in the small stable used by his animals.

It was there that the child was born, surrounded by beasts of the field. As the night's cold grew, the baby fretted and cried while his parents pondered how to make him comfortable. His father tried stuffing straw into the open places in the walls, and his mother tried warming him with her meager wrappings. But still, the baby cried on.

All the while, a tiny kitten watched from the corner. "Of course the little baby is cold," she thought. "It has no fur to keep it warm! I will give it mine, and I will lullaby-purr it to sleep."

A little jump brought the kitten into the manger where the baby lay. There, she quietly gave her humble gift of warmth and love, gently stretching out her thin, fragile little body over the baby's, careful to cover all but the infant's face. The crying was soon replaced by soft purrs and coos, and slowly, the infant smiled.

As Mary, the new mother, witnessed this gift to her child, she touched the little cat's forehead.

"Thank you, Little Tabby, for your gift of love and warmth. As a sign of my grateful blessing, you and all your descendents will forevermore carry my initial on your forehead."

And to this day, tabby cats are known by the remarkable "M" on their foreheads, and by their extraordinary gifts of love, so gently given.

 Xander does have the "M"...but sometimes his love is more gently given than others. And Willow needs to be nominated for sainthood!