Traces of one of the Sheikhs of Tabriz mentioned in Sa di's Bustan

In none of the commentaries on the Bustan, there is any reference to the man intended by Sa’di in the following couplet:ÚÒیÒی ÏÑ ÇÞÕÇی ÊÈÑیÒ ÈæÏ
˜å åãæÇÑå ÈیÏÇÑ æ ÔÈ ÎیÒ ÈæÏ
(there was a dear man in Tabriz / who was always wakeful and vigilant)
Based on the existing evidence, the author of Rowzat al-Jenan wa Jannat al-Janan, quoting his teacher Badr al-Din Ahmad Lalehei, for the first time declares the person referred to by Sa’di as being Sheikh Abubakr b. Solleh-baf of Tabriz, an unidentified mystic of the late 6th/12 century and beginning of the 7th/13 century, Shams-e Tabrizi’s mentor. Apart from one or two scattered pieces of information, nothing is known about him. The main sources of this small information, are Maqalat-e Shams (Shams’s Discourses) and The Manaqeb al-Arefin (Virtues of the Mystics). Even though Ustad Foroozanfar expresses, in a gloss in his Mawlana’s Biography, that Ferydun Sepahsalar has made a reference to Sheikh Abubakr, no mention of such a person is made in the Resale-ye Sepahsalar.
In the present article, the writers have first tracked Sheikh Abubakr Solleh-baf in the sources of that period. Then, by matching Sheikh Abubakr’s mystical states against the contents of the story related in the Bustan, and considering other indications, they have concluded that the person (aziz) referred to by Sa’di is this same Sheikh Abubakr to whom Sa’di apparently paid a visit on his return journey from Mecca to Tabriz.