How to parse. ...

280 RELATIVE PRONOUNS. [Par. 500.

that," we must distinguish the Conjunctive use
in(1) "It was then that the Danes first came to
England."
Here the words " that the Danes... England " are
equivalent to "The Danes' invasion of England;"
"it" is redundant (see Par. 162), and the sentence is
"The Danes' invasion was, i.e. took place, then."
But " that" seems not a Conjunction but a Relative Pronoun in -
(1) " It was of you that I spoke."
This is the same as(2) "It was you that I spoke of, or mentioned,"
where " that " is clearly Relative.
Hence it would seem that " It was of you that I
spoke " is a transposition of " It that I spoke of was
you." On the other hand, in " It was owing to you
that I failed," the meaning is " My failure was
owing to you," and " that" would appear to be a
Conjunction.