Ǽ-fæstnes

According to the Old English Dictionary:

-festnes, -nys, -ness, e;

ǽ-fæstnes

f. Firmness in the law, religion; religio :-- He wæs mycelre ǽfæstnesse wer he was a man of much religion, Bd. 4, 31; S. 610, 7: 2, 9; S. 510, 30, 32. æ-fæstnes