Original: Arrived at this stage of development, the Annals now began to lose their primitive character, and henceforward became more and more indistinguishable from the Chronicles, though the term was still used for many documents, such as the Annals of Waverley.
Simplified: At this stage, the Annals now began to lose their primitive character, and became more and more Chronicles. But the term was still used for many documents, such as the Annals of Waverley.