Answer:
The Magisterium, or Authority within the Anglican Church is Revelation, Scripture and the Holy Tradition, the Seven Ecumenical Councils!
Initially Christ sent the Apostles out in to the world to spread his Gospel and they in turn caused their authority to devolve upon the College of Bishops ! The Seven Ecumenical Councils are ,we are told, "The pillar and ground" of the Church and they complete ,interpret and explain our scriptures. They are the, or a, means by which the Holy Ghost ,the third member of the Holy Trinity involves Himself in the workings of the Church here on earth!
Of the Seven Councils , the first four deal with Christological matters,
the next two are explanatory and the final one was explained by Bishop Field of Chester as , 'a matter of manners'! It dealt with the Church's attitude to the Saints and in particularly to the Lady Mary! The Mother of God!
In 1536 the Convocation of the Anglican Church met and
"The Rule of Faith was declared to be the whole canon or body of the Bible and three Creeds expounded to the sense or import of the words and according to the Doctors of the Church and all opinions were declared erroneous which had been condemned by the Four Councils of Nice, Constantinople, Ephesus and Chalcdon and all other Councils ',sith,' that time which were in any point consonant to the same!"
[ Canon Dixon's Hist.of the Church. Vol 1 pg 416.]
This stand was made at the very beginning of the Reformation in England [1530/1660] and placed the Anglican Church firmly on the catholic side of the struggle . It was stoutly re-affirmed in 1537/1543 and by the State in 1559 Eliza;s Act of Supremacy] A further commitment to catholicity was made with the canons of 1571.
The 39 Articles are not part of the Anglican Canon, instead they were lines in the sand across which the wild men of that time, Anglo Papalists and Calvinists alike, were not allowed to pass.! They should ,Kidd claimed, be viewed through the prism of the Ecumenical Councils. [Kidd. 39 Articles. SPCK.]