Complex sentence: In December 1259, Louis IX of France ceded, to Henry, land north and east of Gascony; in return Henry renounced his claim to many of the territories that had been lost by King John.
Split into simpler sentences: In December 1259, Louis IX of France ceded to Henry land north and east of Gascony. In return, Henry renounced his claim to many of the territories that had been lost by King John.