There are two major love stories in The Pillars of the Earth, and both involve that delight for any storyteller: unlikely, mismatched couples. To work at all, such relationships first have to be shown as feasible in their context: in this case, England of the early Middle Ages. Once that's been established, it falls to the writer not only to make the relationships keep working, but also to make them entertaining, sympathetic and exciting for the reader. Unfortunately for the characters, this usually means putting them through hell! There are proverbs and quotations about the course of true love, and in fiction, guiding that course straight onto the rocks is just the start. Then it gets worse; much, much worse.
In the early 12th century, it's entirely possible that a skilled master craftsman like Tom Builder (Rufus Sewell) might meet and fall in love with someone like Ellen (Natalia Wörner). She begins as the tomboy daughter of a rough country knight and eventually becomes a novice nun. Now all that's in the past, and she's a mysterious wolfish woman who lives with her son in a cave in the woods.
But when they first meet, Tom is still married and has two children of his own; by their second meeting, he's shattered by being recently widowed, something for which Ellen might even be to blame. She has a secret that already brought tragedy into her life, and her reputation around Kingsbridge is that of a witch. It's immediately clear to the audience that if this couple have more than a brief encounter, the life they're going to share will be, to say the least, interesting.
What motivated the love story between Aliena and Jack