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Se mōnaþ is ānhād oþþe stycce tīman, gebrȳced mid gerīmbōcum, þe is ābūtan swā lang swā sum gebyrde fæc gelenge þǣm færelde þæs mōnan (þ.i. "mōna-þ").

mōnaþlengþa

Mōnþas in the Julian and Gregorian calendars 

Sēo Gregorisce gerīmbōc, swā sēo Iulanisce gerīmbōc ǣr hire, hæfþ twelf mōnþas:

 Se æfterra Gēola, mid 31 dagum;
 Solmōnaþ, mid 28 dagum oþþe 29 in bises;
 Hrēþmōnaþ, mid 31 dagum;
 Ēastermōnaþ, mid 30 dagum;
 Þrimilcemōnaþ, mid 31 dagum;
 Sēremōnaþ, mid 30 dagum;
 Mǣdmōnaþ, mid 31 dagum;
 Wēodmōnaþ, mid 31 dagum;
 Hāligmōnaþ, mid 30 dagum;
 Winterfylleþ, mid 31 dagum;
 Blōtmōnaþ, mid 30 dagum;
 Gēolmōnaþ, mid 31 dagum.

Þrēotig dagas hæfþ Hāligmōnaþ,
Ēastermōnaþ, Sēremōnaþ, and Blōtmōnaþ;
Ælc þǣre lāf hæfþ ān and þrēotig,
Būton āne Solmōnaþ,
Sēo hæfþ eahta and tweontig gemænelīce,
Oððæt bisses wyrht hit nigon and tweontig.

oþðe to endenne:

Sēo hæfþ eahta and tweontig gemænelīce,
And nigon and tweontig in ælcum bises.

See also 
 Table of lunar month correspondences

Gerīmbōc