Joseph Pearce in his The Quest for Shakespeare argues convincingly for the Catholicism of  William Shakespeare.  Pearce builds his position with scholarship and logic like a gothic arch;  one pillar rising on biographical evidence and the other from the text of Shakespeare’s  works.

From The Merchant of Venice, when Portia speaks to Shylock,  Act IV, Scene I:

The quality of mercy is not strained.
It droppeth as the gentle rain from heaven
Upon the place beneath.  It is twice blest:
It blesseth him that gives and him that takes.
Tis mightiest in the mightiest; it becomes
The throned monarch better than his crown.
His scepter shows the force of temporal power,
The attribute to awe and majesty,
Wherein doth sit the dread and fear of kings.
But mercy is above this sceptered sway;
It is enthroned in the hearts of kings;
It is an attribute of God himself;
And earthly power doth then show like God’s
When mercy seasons justice.

William Shakespeare
1600