This stele lists 22 statues of The Temple of Isis at Giza and very clearly states that Khufu erected a monument near the Sphinx; therefore the statue must have existed prior to the rule of Khufu and so earlier than Khafre.
Gigal cites the Dream Stele of Thutmose IV - which clearly shows two sphinxes - and the Inventory Stele which seems to indicate a second sphinx destroyed by a storm.
And this is why, even when people see the Sphinx from far away, they can feel that magic. Dobrev also agrees with Stadelmann that Khafre's complex was oriented to the Sphinx rather than the statue being carved during or shortly after construction. A giant recumbent lion with the head of a man sitting in the midst of an ancient plateau begs to have a reason given for it and a history commensurate with the fascination it has inspired over the centuries.
Dobrev, as noted, claimed in that the statue was completed by Khafre's brother Djedfre in honor of his father Khufu and that the face of the statue resembles Khufu's far more than Khafre's.
Athanasius Kircher who never visited Egypt depicted the Sphinx as a Roman statue, reflecting his ability to conceptualize Turris Babel, To this day, we are not completely sure of what lies beneath the Great Sphinx of Giza.
You might not believe this, but we are no way close to surveying every bit of the Egyptian desert. The earliest artistic depictions of "sphinxes" from the South Asian subcontinent are to some extent influenced by Hellenistic art and writings.