On what date were four early demos for Metallica's 1991 self-titled album recorded?

Four early demos for Metallica's 1991 self-titled album, commonly called The Black Album, were recorded on August 13, 1990.

The demos were for “Enter Sandman,” “The Unforgiven,” “Nothing Else Matters,” and “Wherever I May Roam.” They captured the project before the band completed the final arrangements and production decisions that would define the released album.

These recordings came during the songwriting stage, before the main sessions began at One on One Recording Studios in October 1990. The band wrote the album's songs in about two months during mid-1990, with James Hetfield and Lars Ulrich handling most of the writing and Kirk Hammett and Jason Newsted contributing ideas.

“Enter Sandman” has a particularly unusual chronology: it was the first song written for the album but the last to receive lyrics. A separate demo of “Sad but True” was recorded on October 4, 1990, which is why that date should not be confused with the four-demo session.