Complex sentence: Mr. Cole has held master-classes all over the world and although he has recently retired from teaching at the Curtis Institute, he continues to teach at the Temple University preperatory division with his assistant Metta Watts.
Split into simpler sentences: Mr. Cole has held master-classes all over the world. He recently retired from the Curtis Institute, but continues to teach at the Temple University in the preperatory division with his assistant Metta Watts.