Note 13 — Chapter XVI
Reading edition
"The correct system lays down three principles. First, Easter day must be always a Sunday, never on but next after the fourteenth day of the moon; secondly, that fourteenth day of the full moon should be that on or next after the vernal equinox; and thirdly, the equinox itself was invariably assigned to the 21st of March" (Dr. Healy's "Ireland's Schools and Scholars," p. 234). At Rome the 18th had been regarded as the equinox; St. Patrick, however, rightly laid it down that the equinox took place on the 21st.