Gyrstan-dæg
Bosworth & Toller Anglo-Saxon Old English Dictionary - gyrstan-dæg
According to the Old English Dictionary:
gestran-dæg, gysternlíc-dæg YESTERDAY; heri :-- Gyrstan-dæg
- gyrstan-dæg
- heri, Ælfc. Gr. 38; Som. 39, 57. Swá he wæs gyrstan-dæg and ǽran dæg sicut erat heri et nudius tertius, Gen. 31, 5. gyrstan-dæg