CONJUNCTIONS. Whereas for "where"Whereas, on the other hand, is used for where in
“They back returned to the princely place;
“Unto St. Alban's
Whereas the king and queen do mean to hawk.
Whereas . . . a knight . . . they new arrived find.” SPENS. F. Q. i. 4. 38. So
. Probably both "as" and "that" were added to give a relative meaning to the (originally) interrogative adverb where. See 287.