When was the digital computer invented?

Some believe the first such invention occurred in 1944. However, there is strong evidence that the Atanasoff-Berry computer was invented and "reduced to practice" in 1939 at Iowa State University, and that portions were copied by the ENIAC inventors. This was determined in 1973 by a federal court presiding over a patent case between Honeywell and Sperry Rand. In similar developments, Colossus was the first electronic computer (that was developed by the British) to crack the LORENZ codes used by the German high command. The existence of Colossus remained a secret long after WWII. Until recently ENIAC was thought to be the first (although later than Atanasoff-Berry), but the secrecy of Colossus was finally lifted and we find it (and 9 others) were first operational in Jan 1944 while various portions of ENIAC were made operational in the period of June 1944 through October 1945. There are yet others who believe earlier calculators qualify as the first "digital computers".