Den of Thieves

Enter a world of darkness and danger, honour, daring and destiny in David Chandler's magnificent epic trilogy: The Ancient Blades. Croy is a knight errant, and bearer of an ancient blade with a powerful destiny. He's also kind of, well, dim. He believes in honour. He believes that people are fundamentally good, and will do the right thing if you give them a chance. Unfortunately, Croy lives in the city of Ness.
A thriving medieval city of fifty thousand people, none of whom are fundamentally even decent, and who will gleefully stab you in the back. If you give them a chance. Ness is also the home to Malden. Malden is a thief. He lives by his wits, disarming cunning traps, sneaking past sleeping guards, and running away very fast whenever people are trying to kill him. Which is often. One time Malden stole a crown.
And then he had to steal it back to avoid a civil war. Croy got the credit, of course, because he's a noble knight. Another time the two of them went into the tomb of an ancient warrior race, and Croy accidentally started a barbarian invasion. Guess who had to clean that up? They probably wouldn't be friends at all if it wasn't for Cythera. Cythera is a witch. A mostly-good witch. And despite herself she can't stop thieves and knights falling in love with her.
At the same time.