Definition of "sanctitude"

[...] in thir looks Divine / The image of thir glorious Maker ſhon, / Truth, Wiſdome, Sanctitude ſevere and pure, / Severe, but in true filial freedom plac't

1667, John Milton, “Book VI”, in Paradise Lost. […], London: […] [Samuel Simmons], and are to be sold by Peter Parker […]; [a]nd by Robert Boulter […]; [a]nd Matthias Walker, […]; republished as Paradise Lost in Ten Books: […], London: Basil Montagu Pickering […], 1873, lines 291–294