erial
eagle. This indicates the dominating planet, represented by its symbol,
and its house.

The opening in the eagle's left claw, labeled "Lit. Dom." is the
dominical letter. The first seven days in the month of January are each
assigned one of the letters _a_ through _g_ in order of appearance. The
letter which coincides with the first Sunday within this period is
called the dominical letter, and it serves for the following year. In
leap year, two letters are required, one to February 29th and the letter
next proceeding for the remainder of the year. This letter is used in
connection with establishing the date of Easter Sunday. The date of
Easter regulates the dates of the other movable feasts.

The eagle's right claw is labeled "Cyc. EpEC" and represents the epact,
or the age of the moon on January 1st. It serves to find the moon's age
by indicating the number of days to be added to each lunar year in order
to complete a solar year. Twelve lunar months are nearly 11 days short
of the solar year, so that the new moons in one year fall 11 days
earlier than they did the preceding year. However, 30 days are deducted
as an intercalary month since the moon has made a revolution in that
time, and the remainder, 3, would be the epact.

Below the imperial eagle two winged cherubs support a riband with three
indictions of the Julian period. This period of 7980 years is the
product derived from multiplying together the sums of 28, which
represents the cycle of the sun; 19, representing the cycle of the moon;
and 15, which represents the Roman indiction. The Julian period is
reckoned to have begun from 4713 B.C. so that the period will be
completed in A.D. 3267. The first of the three openings is marked "Ind.
Rom." or "Roman indiction," which was an edict by the Emperor
Constantine in A.D. 312, providing for the assessment of a property tax
at the beginning of each 15-year cycle. It continues to be used in
ecclesiastical contracts. The second opening, which occurs immediately
below the eagle, is marked "Cyc. Sol." (cycle of the sun). This cycle
takes a period of 28 years, after which the days of the week once again
fall upon the same days of the month as they did during the first year
of the former cycle. There is no relationship with the course of the sun
itself, but was invented for the purpose of determining the dominical
letter which designates the days of the month on which the Sundays occur
during each year of the cycl