Complex sentence: Joscelin befriends Bran, a young boy at Saint Giles, who obtains vellum on which Joscelin writes a message to Simon arranging a meeting with Iveta and leaves the message in Simon's horse's mane.
Split into simpler sentences: Joscelin befriends Bran, a young boy at Saint Giles, who obtains vellum on which Joscelin writes a message to Simon arranging a meeting with Iveta. He leaves the message in Simon's horse's mane.