Birthdays, anniversaries of the day of birth. The practice of marking an individual's exact date of birth came into existence only with the reckoning of time by a fixed calendar. The custom of observing birthdays, although an ancient one and at present very popular in many countries, is far from being universal.

One of the first birthday celebrations recorded was that of the Pharaoh mentioned in the Bible, who on his birthday made a feast for all his servants (Genesis 40:20). Another birthday mentioned in the Bible was that of King Herod Antipas (Mark 6:21), who celebrated his birthday by holding a great feast for the Galilean noblemen and army generals. Although the ancient Israelis kept records of the ages of their male citizens, there is no evidence that they had any festivities on the anniversary of the birth date. However, a celebration was held on the weaning of a child at the age of two or three. In the Bible it is said that Abraham made a great feast on the day that Isaac was weaned (Genesis 21:8). The ancient world of Egypt, Greece, Rome, and Persia celebrated the birthdays of gods, kings, and nobles. It was not considered important to mark the birthday of commoners, and especially of women and children. The Romans observed May 24, the birth of Artemis, and May 25, the day of Apollo. They celebrated the occasion with parades, circuses, and chariot races. Plutarch reports the lavish party that Cleopatra gave in honor of Antony's birthday. Also towns, cities, and nations celebrated the birthdays of their patrons.

Organized religions, such as Christianity, Islam, and Hinduism, celebrate the birth dates of their founders. In Christian tradition, children are usually named after saints, and in some countries the observance of the saint's birthday is more important than the child's own.

In the Far East (China, Japan, Korea) on the New Year, people automatically add one year to their ages. The most significant birthdays are celebrated when a man reaches the age of 60 and every ten years thereafter. The reason for this is the belief that youth lasts from birth to 32 years of age, middle age from 32 to 40 years of age, and old age from 40 to 60 years of age, so that a new cycle of life begins at the 61st birthday.

In Europe and America an individual's birthday, especially a child's, is an important occasion often celebrated with a family dinner or a party of friends and the customary giving of gifts. Equivalent to birthdays are the celebrations that mark important stages in an individual's life. The Jewish custom of Bar Mitzvah is the religious initiatory rite for boys reaching 13.

Benet, Sula. "Birthdays." Encyclopedia Americana. 2008. Grolier Online. 14 Dec. 2008 http://ea.grolier.com/cgi-bin/article?assetid=0048200-00.

Happy Birthday Song: 

Stradley, Linda. “History of Birthday Cakes.” What’s Cooking America?. 2004. 12 December. 2008. http://whatscookingamerica.net/History/Cakes/BirthdayCake.htm

Astrology:

Astrological as well as astronomical concepts are based on observations of the regularity or periodicity of the movements of the sun, the moon, the stars, and the planets. For agricultural peoples, such as the ancient Chaldeans, Babylonians, Egyptians, Indians, and Chinese, these regularities and their associations with the seasons, the rains, and the growth cycles of plants were of the greatest importance. The Chaldeans and Babylonians, aided by mathematical conceptions more complex than those available to the Egyptians, developed refined astronomical observations and calendars. Their work was the basis of all subsequent astronomical studies as well as astrological conceptions and traditions. The movements of the heavenly bodies were linked to a complex mythology and cosmology, which, in somewhat modified form, became the basis of astrological interpretations in the West. Their astrological and astronomical studies were preserved and developed further by the Greeks and the Arabs and became increasingly popular in Europe from the 13th century on, when European courts included royal astrologers.

Underlying Chaldean and later astrological concepts is the image of the zodiac, with its series of mythological animals. A different set of zodiacal animals is used as a basis of Chinese astrology, which is the kind that is best known in Japan, Korea, and Southeast Asia. (See also Zodiac.)

Astrological systems, linked to astronomical observations and a highly accurate calendrical system, were developed by the Mayas of southern Mexico and Guatemala. Among the books that the Spanish found at the time of the conquest of Mexico were numerous astrological treatises.

Horoscope. A horoscope is a diagram of the heavenly bodies showing the relative positions of the sun, moon, stars, and planets at a given time. To make up an individual's horoscope, the astrologer must know the exact time and place of his or her birth. Each of the 12 signs of the zodiac is believed to be associated with definite aspects of character, temperament, physiology, aptitudes, and the like. By establishing the relative positions of the heavenly bodies at the exact time of a person's birth, astrologers claim to be able to predict the person's future or advise him or her on courses of action or decisions.

Bourguignon, Erika. "Astrology." Encyclopedia Americana. 2008. Grolier Online. 14 Dec. 2008 http://ea.grolier.com/cgi-bin/article?assetid=0024680-00.

Chinese Birthdays:

For days after the New Year begins, businesses are shut down, and the time is devoted to rest or recreation. It is an especially exciting time for children because they receive presents of money in red envelopes. Birthdays are not celebrated in the same way as in the West, and since ages are figured from the New Year, this replaces the birthday. A child is one year old at birth and two years after the New Year, so that an infant may become two years old in a matter of hours.

Each Chinese year is popularly known by one of the 12 animals of the Chinese Zodiac in the following order: rat (Aries), ox (Taurus), tiger (Gemini), hare (Cancer), dragon (Leo), serpent (Virgo), horse (Libra), sheep (Scorpio), monkey (Sagittarius), cock (Capricorn), dog (Aquarius), and boar (Pisces). These names provide a ready reference to the recent past, especially for the illiterate, because each name is used only once in 12 years.

Shirley, James R. "Chinese New Year." Encyclopedia Americana. 2008. Grolier Online. 14 Dec. 2008 http://ea.grolier.com/cgi-bin/article?assetid=0091530-00.

Calendar:

The kind of calendar adopted by a civilization had a great influence on the development of astronomy in that civilization. If a lunar calendar was used, it sufficed to determine the length of the lunar month fairly exactly; if a solar calendar was used, it sufficed to know the approximate length of the year. Slight alterations of such calendars could easily be made empirically, as needed. To develop a lunisolar calendar, however, it was essential to estimate these units of time much more precisely. Only those ancient civilizations that adopted a lunisolar calendar made real advances in astronomy.

Egyptian Calendar. During the first stages of Egyptian civilization, more than 10,000 years ago, a crude calendar consisting of 12 months of 30 days each was developed. The calendar year thus contained only 360 days. About the year 4000 B.C., however, 5 supplementary days were added at the end of each year; the resulting 365-day year, or vague year, fell behind the solar year 1 day every 4 years. This calendar made no use of intercalations and constituted a scale of unvarying length; this was most important, for it served the Greek astronomers and was still used by Copernicus in the 16th century A.D.

Sothic Period. However, the calendar was inconvenient in that a holiday with a fixed date (such as New Year's day) had to make a complete cycle of the seasons over a period of nearly 15 centuries. That is, since the holiday moved back 1 day every 4 solar years, it came back to its original position in the seasons only after a period of 4 times 365.25, or 1,461 years. This period was called the Sothic period, from the Egyptian name Sothis for the star Sirius, because the Egyptians had observed that the flooding of the Nile began each year at the time of the heliacal rising of Sirius. (The heliacal rising of a star is the first day the star can be seen before sunrise, in the light of dawn.) The Egyptian calendar was divided into 3 seasons of 4 months each, and every 1,461 years the heliacal rising of Sirius fell on New Year's day—thus marking the beginning of a new Sothic period.

In 238 B.C. an edict of King Ptolemy III attempted to correct the vague year by adding another supplementary day every 4 years (the solution later adopted by the Romans and known as the Julian reform). However, the Egyptian people refused to accept the new regulation; for when a third Sothic period ended in Egypt in 139 A.D., the vague year continued to be used afterward.

Babylonian, Assyrian, and Chaldean Calendar. For the civilizations of the Tigris-Euphrates valley, the year began in the spring with the month Nisannu and consisted of 12 lunar months. Each month began in the evening, as soon as the crescent of the new moon appeared. The months were alternately 30 and 29 days long, and the 354-day calendar year fell approximately 1 month behind the solar year by the end of 3 years. Consequently, an extra month was usually added at such times by order of the reigning king. The time for such an intercalation was determined by observing a star whose heliacal rising occurred—at least in principle—in a designated month. Unfortunately, the intercalations were often poorly regulated; it is not uncommon to find records of 2 consecutive 13-month years. Above all, the intercalations were unreliably recorded. Starting in 380 B.C., however, they were codified, with 7 intercalations being made during a 19-year period—the same period as the Metonic cycle that had been developed in Greece 50 years previously. It is not known whether the Babylonians discovered the cycle themselves or borrowed it from the Greeks.

Hebrew Calendar. The ancient Hebrews were not very interested in astronomical studies and seem to have adopted their empirical lunisolar calendar from that of their Babylonian neighbors. The months in the Jewish calendar were either full (30 days) or deficient (29 days) and were regulated as much as possible by lunar events. Intercalations were, for a long time, arbitrarily decided upon by government authorities or, in the first 3 centuries A.D., by the Sanhedrin (the supreme judicial tribunal of the Jews). It was not until the 4th century A.D. that the Jews adopted the 19-year period—the Metonic cycle—in which 7 months are intercalated in order to maintain agreement with the solar year.

This cycle is still used today in the Jewish religious calendar. The additional months are added to the 3d, 6th, 8th, 11th, 14th, 17th, and 19th years of the 19-year period. They are inserted in the middle of the year and repeat the 6th month. Ordinary years may have 353, 354, or 355 days; intercalary years may be 383, 384, or 385 days long. The system offers some other inconvenient complications, in that for religious reasons the year cannot begin on a Sunday, Wednesday, or Friday. The day begins at sunset of the preceding civil day.

The Hebrews can be considered to have established the week as a unit of time. The pivot of the week is the sabbath, or day of rest, which corresponds to the Saturday of the modern calendar.

Chinese Calendar. The ancient Chinese calendar was lunisolar, and the ordinary year contained 12 lunar months. When a 13th month was added in order to reestablish agreement with the solar year, the intercalary year was called a full year. The Chinese year began with the lunar month during which the sun entered the zodiacal sign of Aquarius; thus, New Year's day could fall between January 20 and February 19. For recording historical events, two cycles were used, both 60 years long; in civil life, years were dated from the reigning emperor's ascent to the throne. See also Chinese New Year.

Mayan Calendar. One of the rare preserved manuscripts from the Mayan civilization in the Western Hemisphere provides dates for certain eclipses that occurred in antiquity. These dates, however, were probably the result of calculations rather than actual observations, and the antiquity of Mayan astronomy is therefore not proven by such documents. On the other hand, the very existence of the calculations implies a high level of astronomical achievement, which in turn indicates a long tradition behind it.

Most of the stone-engraved Mayan inscriptions relating to astronomy are dates. The dates extend from the middle of the 3d to the middle of the 6th centuries A.D., but the Mayan method of calculating time was still in use in Mexico when the Spaniards arrived. The days were placed in groups of 20 to make a kind of month, or uinal; and 18 consecutive uinals formed a vague year, or tun, of 360 days. A group of 20 such years was called a katun, and katuns were in turn grouped in 20s. Alternatively, the Mayans also arranged their days within a year that was rounded out to 365 days by adding 5 supplementary days. Finally, days were also arranged within a tzolkin, a 260-day period made up of 13 units of 20 days each. The Mayans did not attempt to link up all these different cycles but allowed the 3 different chronological systems to follow their respective courses.

"Calendar." Encyclopedia Americana. 2008. Grolier Online. 14 Dec. 2008 http://ea.grolier.com/cgi-bin/article?assetid=0071200-03.