Complex sentence: Being more involved in Western European integration, Hallstein delegated much of this work to his deputy, Wilhelm Grewe, but it is in this area, particularly, that German foreign policy is associated with the name Hallstein.
Split into simpler sentences: Being more involved in Western European integration, Hallstein delegated much of this work to his deputy, Wilhelm Grewe. But it is in this area, particularly, that German foreign policy is associated with the name Hallstein.