Complex sentence: Jeremiah began his studies at The College of William & Mary in Virginia, and after serving in the War of 1812, during which he rose to the rank of major, he returned to Virginia to study law.
Split into simpler sentences: Jeremiah began his studies at The College of William & Mary in Virginia. After serving in the War of 1812, during which he rose to the rank of major, he returned to Virginia to study law.