In Sir Gawain and the Green Knight, Gawain takes his leave of Arthur's court so that he will not be late for the meeting with the Green Knight as he had promised a year before.
Though everyone at the court is sorry to see him go, Gawain does the honorable thing, keeping his word, even with his own fears and reservations.
The journey is very difficult as he travels through strange lands. He passes through North Wales and beyond. Of every man Gawain meets, he asks if he can help the knight locate the Green Knight, but no one knows of him.
Traveling into dangerous lands, Gawain battles dragons and trolls, and other sundry animals trying their best to destroy him. He feels blessed by God that he is not killed, but for a time it seems nature may do what the animals could not: Gawain is cold and wet, and at times feels half-dead, surviving in the winter without shelter.
As Christmas approaches, he prays to Mary, the Virgin, to provide shelter and a place where he may celebrate the birth of Christ at Christmas. No sooner has he said so, and crossed himself three times, but he spots a castle nearby.
"I beseech thee, Lord
and Mary, the mildest, dearest of mothers:
Help me to some haven where mass can be heard,
and matins tomorrow...
He continued on his way,
confessing his misdeeds,
and crossed himself to pray,
"Christ's cross now grant me speed!"...
Surely, Gawain thinks, he could impose on the owner's hospitality. He approaches the gate and hails the porter. He asks for shelter, and the porter immediately welcomes him inside.
Here in Bertilak's castle, Gawain will rest and be able to celebrate Christmas mass.