What are the differences between New Historicism and old Historicism?

As New Historicism emerged (via Foucault, Lacan,
Greenblatt, etc.) there was an increase in focus a general diversification of the canon
in efforts to acknowledge previous and current minority literature which had been
suppressed by the white western patriarchy.  Complementing this increase of the canon as
far as recognizing previously suppressed minority literature as elite classics; there
was also a growing interest in pop culture and so-called ‘low-brow’ literature and art.
This had nothing to do with the cultural diversification; it had to do with the change
in historicism where all texts (literary and non-literary) were considered ‘literature’
and products of their historical epoch. I mention the canonical inclusion of minority
literature and pop culture because they represent alternative literatures (to the elite
and the classics) and this was part of the transition from Old to New Historicism: the
recognition of alternative perspectives of history.

Old
historicism (which I would call pre-New Historicism) is similar to New H. in that the
idea is to investigate the historical, social, and cultural world of the author and that
these elements are always interconnected with the literature of their time period. Both
old and new historicists believe that texts cannot be separated from their historical
context.

New Historicism pays more attention to ideology,
power and is just more nuanced than its predecessor. With New H., the critic understands
that there is no objective history and that ideology plays a role in the work of the
critic and the author the critic is analyzing. So, if Foucault is doing an analysis of
The Tempest, he
would:

1)      Recognize
cultural, ideological, economic, etc. elements of Elizabethan England and how they
influenced Shakespeare; AND, he would note where/when Shakespeare was conscious and
unconscious of these elements in his work. He would note that Shakespeare’s work cannot
be completely boiled down to Elizabethan culture since history is not that simple.
So, Foucault can’t look at Shakespeare as an objective filter of his
historical context. He must investigate the historical context, the work and Shakespeare
as a subjective interpreter of his own historical period.

2)     
Foucault would also be conscious of his own subjectivity and historical
biases in his investigation of Shakespeare’s subjectivity and historical interpretation.

I think the biggest difference between Old
and New Historicism is that New takes a more subjective approach; more conscious of
history as interpretation on everyone’s part: author, historicist, historian,
etc.