Start of Yom Kippur War and Egyptian and Syrian attack on Israel (October 6), on this date in 1973, Egyptian and Syrian forces launched a coordinated attack on Israel from the southern and northern fronts. The offensive began on Yom Kippur, a major Jewish religious holiday, catching Israeli forces by surprise. The conflict lasted for about three weeks, resulting in the deaths of over 2,500 Israeli soldiers and an estimated 15,000 Arab troops. The war had significant effects on the political and military landscape of the region and led to major changes in Middle Eastern international relations. This observance was added to the Gregorian calendar in subsequent years to commemorate the historical significance and profound impact of the war on regional and global developments.