Complex sentence: The Mausoleum was mentioned first by Hamdollah Mostowfi in his Nozhat ol-Gholoub in the Surkhab district of Tabriz.
Split into simpler sentences: The Mausoleum was mentioned first by Hamdollah Mostowfi in his Nozhat ol-Gholoub. Hamdollah mentions it being located in then the Surkhab district of Tabriz.