Complex sentence: Sources describe the building of the fort as a matter of self-defence, the Bábí's spent many months under attack in the fort, resorting to eating the leather of their own clothes to remain alive.
Split into simpler sentences: Sources describe the building of the fort as a matter of self-defence. The Bábí's spent many months under attack in the fort, resorting to eating the leather of their own clothes to remain alive.