Shaykh al Islam Ibn taymiyyah revived Syria during the Mongol Invasion.
Ibn al Imad quoted ad-Dhahabi from his book Mu’jam al Shuyukh:
وأحيا به الشام، بل والإسلام، بعد أن كاد ينثلم خصوصا في كائنة التتار، وهو أكبر من أن ينبّه على سيرته مثلي، فلو حلّفت بين الرّكن والمقام لحلفت أني ما رأيت بعيني مثله، وأنه ما رأى مثل نفسه. انتهى كلام الذهبي.
“And he revived Syria, rather, Islam, after it was about to be torn apart, especially during the Mongol invasion. He is too great for me to describe his biography, for if I were to swear between the Corner (of the Kaaba) and the Station (of Ibrahim), I say: I have not seen anyone like him with my own eyes, and he has not seen anyone like himself.
Shadharaat adh-Dhahab fi Akhbar min Dhahab – Ibn al-‘Imad al-Hanbali 8/144