Sir Ian McKellen stands with his two rather motley stunt doubles. It seems that Ian McKellen is not much of a horse person, and therefore every shot in the films with Gandalf riding a horse is actually a stunt double - presumably, one of these guys.
The Hobbit movie is the prequel to the Lord of the Rings. It tells the tale of Bilbo Baggins and his adventures about 60 years prior to the events chronicled in LOTR. Bilbo is an adventurous young Hobbit (actually more adventurous than his nephew.
“I am Aragorn son of Arathorn, and am called Elessar, the Elfstone, Dúnadain, the heir of Isildur Elendil’s son of Gondor. Here is the sword that was broken and is forged again! Will you aid me or thwart me?