In 1544 Henry VIII passed the Third Succession Act, which stated that his son Edward should succeed him, followed by his daughters Mary and Elizabeth, who should only marry with the consent of advisors appointed by the king. The Act also sought to limit the succession by reverting all subsequent decisions, alterations, and revisions of Henry's heirs to the authority of the king's letter patents or to his Will and Testament. In this Will and Testament, which was drawn up in 1546, Henry added further indications concerning alternative successors, should his direct line fail. While he made no mention of the Stewarts, who were descendants of his elder sister, Margaret, he designated Frances and Eleanor Brandon, daughters of the Earl of Suffolk, and their heirs, as being descendants from his younger sister, Mary. The Will and Testament concluded by stating that, if the Suffolk line bore no legitimate offspring, the ‘next rightful heirs’ should succeed to the throne; the document failed to specify who these heirs might be. The authenticity of the will was questioned for decades, since it was stamped and not signed by the king, who was then on his deathbed, and so considered by some to be ‘past sense and memory’.

After the early deaths of Edward VI, Lady Jane Grey, and Mary, Elizabeth became Queen of England in accordance the Third Succession Act. Nevertheless, there were shadows cast on her claims. Henry's Second Succession Act of 1536 had decreed her illegitimate after his divorce from Anne Boleyn. Coupled with the doubtful nature of Henry VIII's testament, the interpretation of these documents sparked harsh debates on who should be deemed the lawful heir to the throne after the death, and even instead of, Elizabeth.