Complex sentence: At the age of 13 he was apprenticed to Thomas W. Knight, and on the expiration of his apprenticeship he worked in the studio of the Chevalier Ballin, whose influence is evident in Josey's work in stipple and line.
Split into simpler sentences: At the age of 13 he was apprenticed to Thomas W. Knight, and on the expiration of his apprenticeship he worked in the studio of the Chevalier Ballin. Ballin's influence is evident in Josey's work in stipple and line.