+---+ | G | +---+ GLASS BOX TESTING (See structural test case design) GREGORIAN CALENDAR. Today's general-use calendar of 12 months and 365 days that employs the current leap year algorithm (refer to LEAP YEAR below). (IBM) GREGORIAN CALENDAR The Venerable Bede, an Anglo-Saxon monk, announced in A.D. 730 that the 365 1/4-day Julian year was 11 m in, 14 sec too long, a cumulative error of about a day every 128 years, but nothing was done about it for more than 800 years. By 1582 the accumulated error was estimated to amount to 10 days. In that year Pope Gregory XIII decreed that the day following Oct. 4, 1582, should be called Oct. 15, thus dropping 10 days and initiating what became known as the Gregorian calendar. However, with common years 365 days and a 366-day leap year every fourth year, the error in the length of the year would have recurred at the rate of a little more than 3 days every 400 years. Therefore, 3 of every 4 centesimal years (years ending in 00) were made common years, not leap years. Thus, 1600 was a leap year; 1700, 1800, and 1900 were not, but 2000 will be. Leap years are those years divisible by 4, except centesimal years, which are common unless divisible by 400. The Gregorian calendar was adopted at once by France, Italy, Spain, Portugal, and Luxembourg. Within 2 years most German Catholic states, Belgium, and parts of Switzerland and the Netherlands were brought under the new calendar, and Hungary followed in 15 87. The rest of the Netherlands, along with Denmark and the German Protestant states, made the change in 1699-1700 (German Protestants retained the old reckoning of Easter until 1776). The British government imposed the Gregorian calendar on all its possessions, including the American colonies, in 1752. The British decreed that the day following Sept. 2, 1752, should be called Sept. 14, a loss of 11 days. All dates preceding were marked O.S., for Old Style. In addition, New Year's Day was moved to Jan. 1 from Mar. 25 (e.g., under the old reckoning, Mar. 24, 1700, had been followed by Mar. 25, 1701). George Washington's birthdate, which was Feb. 11, 1731, O.S., became Feb. 22, 1732, New Style (N.S.). In 1753 Sweden too went Gregorian, retaining the old Easter rules until 1844. In 1793 the French revolutionary government adopted a calendar of 12 months of 30 days each with 5 extra days in September of each common year and a 6th extra day every 4th year. Napoleon reinstated the Gregorian calendar in 1806. The Gregorian system later spread to non-European regions, first in the European colonies and then in the independent countries, replacing traditional calendars at least for official purposes. Japan in 1873, Egypt in 1875, China in 1912, and Turkey in 1917 made the change, usually in conjunction with political upheavals. In China, the republican government began reckoning years from its 1911 founding - e.g., 1948 was designated the year 37. After 1949, the Communists adopted the Common, or Christian Era, year count, even for the traditional lunar calendar. In 1918 the revolutionary government in the Soviet Union decreed that the day after Jan. 31, 1918, O.S., would become Feb. 14, 1918, N.S. Greece followed in 1923. (The Russian Orthodox Church has retained the Julian calendar, as have various Middle Easter n Christian sects.) For the first time in history, all major cultures have one calendar. To convert from the Julian to the Gregorian calendar, add 10 days to dates Oct. 5, 1582, through Feb. 28, 1700; after that date add 11 days through Feb. 28, 1800; 12 days through Feb. 28, 1900; and 13 days through Feb. 28, 2100. A century consists of 100 consecutive calendar years. The 1st century AD consisted of the years 1 through 100. The 20th century consists of the years 1901 through 2000 and will end Dec. 31, 2000. The 21st century will begin Jan. 1, 2001. (FW) 1752 AD, Britain and her colonies adopt the Gregorian calendar of 1582 (the difference between the Old Style Julian calendar of 46 B.C. and the Gregorian calendar has grown to 11 days). Thursday, September 14, follows Wednesday, September 2, by decree of Parliament, the change confuses bill collectors, rumors spread that salaried employees are losing 11 days' pay and that everybody is losing 11 days of his life, Londoners cry, "Give us back our 11 days," and there are riots to protest the calendar change. (PC) 1572 AD, The Vatican asks an astronomer to correct the Julian calendar in use since 46 B.C. because it is too long by 11 minutes and 15 seconds each year, but the astronomer will die before he can reform the calendar (PC) Gregorian Calendar Choose the desired year from the table below (for years 1803 to 2080). The number shown with each year designates which calendar to use for that year. (The Gregorian calendar was inaugurated Oct. 15, 1582. From that date to Dec. 31, 1582, use calendar 6.) 1583 7 1603 4 1623 1 1643 5 1663 2 1683 6 1703 2 1723 6 1743 3 1763 7 1783 4 1584 8 1604 12 1624 9 1644 13 1664 10 1684 14 1704 10 1724 14 1744 11 1764 8 1784 12 1585 3 1605 7 1625 4 1645 1 1665 5 1685 2 1705 5 1725 2 1745 6 1765 3 1785 7 1586 4 1606 1 1626 5 1646 2 1666 6 1686 3 1706 6 1726 3 1746 7 1766 4 1786 1 1587 5 1607 2 1627 6 1647 3 1667 7 1687 4 1707 7 1727 4 1747 1 1767 5 1787 2 1588 13 1608 10 1628 14 1648 11 1668 8 1688 12 1708 8 1728 12 1748 9 1768 13 1788 10 1589 1 1609 5 1629 2 1649 6 1669 3 1689 7 1709 3 1729 7 1749 4 1769 1 1789 5 1590 2 1610 6 1630 3 1650 7 1670 4 1690 1 1710 4 1730 1 1750 5 1770 2 1790 6 1591 3 1611 7 1631 4 1651 1 1671 5 1691 2 1711 5 1731 2 1751 6 1771 3 1791 7 1592 11 1612 8 1632 12 1652 9 1672 13 1692 10 1712 13 1732 10 1752 14 1772 11 1792 8 1593 6 1613 3 1633 7 1653 4 1673 1 1693 5 1713 1 1733 5 1753 2 1773 6 1793 3 1594 7 1614 4 1634 1 1654 5 1674 2 1694 6 1714 2 1734 6 1754 3 1774 7 1794 4 1595 1 1615 5 1635 2 1655 6 1675 3 1695 7 1715 3 1735 7 1755 4 1775 1 1795 5 1596 9 1616 13 1636 10 1656 14 1676 11 1696 8 1716 11 1736 8 1756 12 1776 9 1796 13 1597 4 1617 1 1637 5 1657 2 1677 6 1697 3 1717 6 1737 3 1757 7 1777 4 1797 1 1598 5 1618 2 1638 6 1658 3 1678 7 1698 4 1718 7 1738 4 1758 1 1778 5 1798 2 1599 6 1619 3 1639 7 1659 4 1679 1 1699 5 1719 1 1739 5 1759 2 1779 6 1799 3 1600 14 1620 11 1640 8 1660 12 1680 9 1700 6 1720 9 1740 13 1760 10 1780 14 1800 4 1601 2 1621 6 1641 3 1661 7 1681 4 1701 7 1721 4 1741 1 1761 5 1781 2 1801 5 1602 3 1622 7 1642 4 1662 1 1682 5 1702 1 1722 5 1742 2 1762 6 1782 3 1802 6 (FW)