Complex sentence: Regular regiments gained auxiliary battalions through the integration of the militia and volunteers, of which nine from Lancashire and the Isle of Man transferred to the King's and ultimately became part of the Special Reserve and Territorial Force.
Split into simpler sentences: Regular regiments gained auxiliary battalions through the integration of the militia and volunteers. Nine militia and volunteer battalions from Lancashire and the Isle of Man transferred to the King's, and ultimately became part of the Special Reserve and Territorial Force.