Definition of "whereout"

There was one upon a time, who being of this mind, that there was nothing ſo honeſt as to crave and receive, begged of Archelaus the king of Macedonie (as he ſate at ſupper) the cup of golde whereout he drunke himſelfe; […]

1603, Plutarch, “Of Vnseemely and Navghty Bashfvlnesse”, in Philemon Holland, transl., The Philosophie, Commonlie Called, The Morals […], London: […] Arnold Hatfield, page 167