Who was the master of that Lodge at the time?
The entire matter of who did the initiation of Prince Hall and the other 14 members of African Lodge No. 1 revolve around when the initiation was done.
According to record attached to this comment (Thanks to Bro. Mark), John Batt was the first Master of the Lodge until after June 1778.
The first thing you will notice on the record is the top portion that says, "Boston March 6, 1778", there is another document that shows what John Batt was paid that proves that this was the date of the initiation.
The Second thing you will notice is that the records shows that EAs, FC and Masters were MAID BY, the worthy and amiable GRAND MASTER BATT.
This immediately raises questions, because according to the Grand Lodge of Ireland, John Batt was never a Grand Master of their Grand Lodge, which is the only means by which any member under their Jurisdiction could designate themselves as such. This come directly from the Grand Archivist, Rebecca Hayes.
John Batt was neither a Grand Master under St, Andrew's (Scottish) or St. John's (Moderns) Provincial Grand Lodges in Boston (where he resided in March of 1778). So, it shows that John Batt was considered the first Master of African Lodge No. 1 prior to the Charter in 1784. As you can see in the third column, under masters, Prince Hall is also listed as GRAND MASTER (or the head of the Lodge). This tells us that the document was composed after March 6, 1778, at a time when Prince Hall had taken charge of the Lodge, after the desertion of John Batt. We know this for certain, because Prince Hall in a December 28, 1778 record was now doing the initiation.
What is most interesting about this point is that the record shows THREE COLUMNS, one for EA, the other for FC and Master, and you will see that most of the names are the same throughout the columns, which shows a progression of a particular member through the degrees. What has to be paid attention to is that the Masters column has dates associated with the names, and those dates are when those members were MAID MASTERS. And, all of them are AFTER March 6, 1778, with the exception of Prince Hall. We know that Prince Hall was initiated on March 6, 1778 (not raised), because his name appears on the listing of those INITIATED on March 6, 1778. So, the initiation didn't happen on March 6, 1775, but on March 6, 1778; this would exclude Irish Military Lodge from taking part in this initiation, because they were in New York fighting the New York Campaign. Irish Military Lodge eventually became a founding lodge of the Grand Lodge of New York (MS) in 1781, they eventually left New York for England in 1783.
So, according to the records, John Batt was the FIRST MASTER, and he did the initiations all by his lonesome...African Lodge No. 1 was not a regular group until 1784, six years after their initial Initiation....