Which preposition to use with unforgetful

of Occurrences 2%

Like the low murmurs of the Indian shell Ta'en from its coral bed beneath the wave, Which, unforgetful of the ocean's swell, Retains within its mystic urn the hum Heard in the sea-grots where the Nereids dwell Old thoughts still haunt meunawares they come Between me and my rest, nor can I make Those aged visitors of sorrow dumb.

Which preposition to use with  unforgetful