Complex sentence: Safdarjung was made the Chief Minister of the empire with the title of Wazir ul-Mamalk-i-Hindustan and at that time the empire was on decline as their rule extended only to North India.
Split into simpler sentences: Safdarjung was made the Chief Minister of the empire with the title of Wazir ul-Mamalk-i-Hindustan. At that time the empire was on decline as their rule extended only to North India.