Wonders of the East and Astronomical-Calendrical Treatise

original: "Sum Liber Radulphi Malerardi"

[Folio Left]

Solar concurrents concurrent|A number (1–7) representing the day of the week for a specific date in the solar cycle, used to find the day of the week for any date in the year. and lunar epacts epact|The age of the moon in days on January 1st, essential for calculating the date of Easter.

Place the regulars regular|Fixed numbers assigned to months to assist in calendar calculations. above; add the concurrent of whatever year you wish to them. If you divide the sum by 7, the remainder will be the letter indicating which day of the week the Kalends Kalends|The first day of the month in the Roman calendar. of April will be. This is the place of the concurrent, because for whichever day of the week it results in... ies?... ex?plonit... weeks... will be in that same year.

In truth, all months have eight Ides Ides|A division of the Roman month, usually falling on the 13th or 15th.. January, March, May, July, August, and October have 6 Kalends [before the Nones]. December has 4 Kalends. They have 18 Kalends. They have 19 Kalends after the Ides, and after the Ides, and days 25 ones. 25 one. The scribe is listing the number of days between major calendar markers; the phrasing is shorthand and somewhat repetitive.

Thus begins the method of calculation. April. The year is February for the epact. And November. The Kalends have 15. December. 4 Kalends. 18 Kalends after the Ides. And 28 days. And thirty days. If it is a leap year original: "bissextus", 29.

Join the regulars of the individual months with the epacts of whatever year. And if it is 25, that is the age of the moon. In the 6th Kalends of April, to find the epacts from the moon: however many days the age of the moon is there, it will have that many epacts in that year.

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[Folio Right]

The right side of this folio contains a vertical column of text, likely a continuation of the calendrical tables or rules found on the left, but it is too faded for reliable transcription.

... in this ...
... months ... days ...
... solar ...
... and ...
...

The following list of terms relates to the science of Computus—the medieval study of time and the calculation of feast days.
epacts|The excess of the solar year over the lunar year, used to track the moon's age., concurrents|The days added to the solar cycle to align it with the week., months|The twelve divisions of the year., ides|The middle of the month., kalends|The start of the month., leap year|A year with an extra day (February 29th)., computus|The mathematical calculation of the calendar., regulars|Fixed values used in calendar equations.