Tomorrow is Dec. 25 - Christmas - for those of the Eastern Orthodox Church who still observe the Julian calendar. When the Roman Catholic Church replaced the Julian system with the modern Gregorian calendar in 1582 (not until 1752 in Britain and its colonies), Oct. 5, 1582, became Oct. 15. People were furious that they'd "lost" 10 days of their lives. But the adjustment was needed to get the calendar back in synch with the sun and seasons. The Julian Christmas has slipped three more days since then.