Complex sentence: Jackson notes that nine trains passed through Aleppo between 1 and 19 August, several of which were carrying thousands of Armenians from Ainteb who were subsequently robbed by villagers.
Split into simpler sentences: Jackson notes that nine trains passed through Aleppo between 1 and 19 August. Several of them were carrying thousands of Armenians from Ainteb and were subsequently robbed by villagers.