AI overview
I don't have enough context to write an accurate overview of what "900" refers to. The context provided only indicates "year," but doesn't specify whether this is about the year 900 CE, a historical event, or something else entirely. Could you provide more details about what "900" refers to?
AI-generated from the Wikipedia summary — may contain errors.
Article
The Earth's Eastern Hemisphere (c. 900) Gunnbjörn discovers Greenland (c. 900)
Year 900 (CM) was a leap year starting on Tuesday of the Julian calendar.