I do not know the date of his muster; it was somewhat delayed, but was probably dated back to about that time.
Recruiting for the Fifty-Fourth Massachusetts (colored) began on February 9, 1863, and the first squad went into camp at Readville, Massachusetts, on February 21, 1863, numbering twenty-five men.

Colonel Shaw's commission (and probably his muster) was dated April 17, 1863.
(Report of Adjutant-General of Massachusetts for 1863, pp.

896-899.) These were the earliest colored regiments, so far as I know.
Appendix C General Saxton's Instructions [The following are the instructions under which my regiment was raised.
It will be seen how unequivocal were the provisions in respect to pay, upon which so long and weary a contest was waged by our friends in Congress, before the fulfilment of the contract could be secured.] WAR DEPARTMENT, WASHINGTON CITY, D.C., August 25, 1862.
GENERAL, Your despatch of the 16th has this moment been received.

It is considered by the Department that the instructions given at the time of your appointment were sufficient to enable you to do what you have now requested authority for doing.

But in order to place your authority beyond all doubt, you are hereby authorized and instructed, 1st, To organize in any convenient organization, by squads, companies, battalions, regiments, and brigades, or otherwise, colored persons of African descent for volunteer laborers, to a number not exceeding fifty thousand, and muster them into the service of the United States for the term of the war, at a rate of compensation not exceeding five dollars per month for common laborers, and eight dollars per month for mechanical or skilled laborers, and assign them to the Quartermaster's Department, to do and perform such laborer's duty as may be required during the present war, and to be subject to the rules and articles of war.
2d.