Q:

Fantasy story of a prince's unwanted brother

I'm trying to remember the title of a fantasy story in which the main character is the unwanted brother (or half-brother?)  of a prince.  Other important characters are an older brother who is assassinated and a crippled stableman. 
This story haunts me, as I never finished it.  I believe it is part of a series I picked up at the library. 

A:

The Farseer trilogy by Robin Hobb (who also writes as Megan Lindholm).  The three volumes are Assassin's Apprentice, Royal Assassin and Assassin's Quest.