Final answer:
Haec Dies is a Latin phrase that translates to This is the day. It is part of a poem written by William Byrd, an English composer in the 16th century. The poem contemplates life and death and emphasizes the importance of appreciating each day.
Step-by-step explanation:
Haec Dies is a Latin phrase that translates to This is the day. The source text of Haec Dies is a poem written by the English composer William Byrd in the 16th century.
In the poem, Byrd contemplates life and death, questioning the purpose and inevitability of death. The lines you provided are a part of the poem and express the poet's struggle with the concept of death and its impact on loved ones.
The phrase 'This is the day' in Haec Dies can be interpreted as a reflection on the transient nature of life and the need to appreciate and embrace each day as it comes.