AI overview
I cannot write an overview of "1521" based solely on the context that it is a "year," as this doesn't provide specific information about what event, work, or subject matter is being referred to. Many significant historical events occurred in 1521 (such as Cortés's conquest of the Aztec Empire, or Luther's appearance at the Diet of Worms), and I cannot determine which one you're asking about without additional context.
AI-generated from the Wikipedia summary — may contain errors.
Article
January 22: The Diet of Worms parliament is opened by Emperor Charles V in the German city of Worms.
1521 (MDXXI) was a common year starting on Tuesday of the Julian calendar, the 1521st year of the Common Era (CE) and Anno Domini (AD) designations, the 521st year of the 2nd millennium, the 21st year of the 16th century, and the 2nd year of the 1520s decade.