Group C blood is different in that it agglutinates with both A and B. This was the discovery of blood groups for which Landsteiner was awarded the Nobel Prize in Physiology or Medicine in 1930. (C was later renamed to O after the German Ohne, meaning without, or zero, or null.) Another group (later named AB) was discovered a year later by Landsteiners students Adriano Sturli and Alfred von Decastello without designating the name (simply referring it to as "no particular type"). Thus, after Landsteiner, three blood types were initially recognised, namely A, B, and C.Czech serologist Jan Janský was the first to recognise and designate four blood types in 1907 that he published in a local journal, using the Roman numerical I, II, III, and IV (corresponding to modern O, A, B, and AB respectively). Unknown to Janský, an American physician William L. Moss introduced almost identical classification in 1910; but his I and IV corresponding Janskýs IV and I. Moss came across Janskýs paper as his was being printed, mentioned it in a footnote. Thus the existence of two systems immediately created confusion and potential danger in medical practice. Mosss system was adopted in Britain, France, and the US, while Janskýs was preferred in most other European countries and some parts of the US. It was reported that "The practically universal use of the Moss classification at that time was completely and purposely cast aside. Therefore in place of bringing order out of chaos, chaos was increased in the larger cities."
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