The Great Pirate Era, or otherwise the Golden Age of Pirates, is a critical epoch within the One Piece realm in which the main storyline is set. It started with Gol D. Roger, also called Pirate King, being executed in 1521 AOS, After the Ocean's Sovereignty. His final words, before his execution, fueled dreams of pirates around the world to go hunting for his legendary treasure, One Piece.
The Great Pirate Era's timeline is very tight to the One Piece timeline. It started about 24 years ago from the point of view of the main storyline, with Monkey D. Luffy finally sailing at age 17, so the beginning of his journey would be around 1524 AOS. This placement in time will allow for at least a generation to rise and fall in piracy before Luffy's adventures begin, thereby enabling or enriching the setting of complicated power dynamics and legendary figures.
Some legendary figures who appeared at the very beginning of the age of great pirates are Edward Newgate, better known as Whitebeard, and others among the Yonko: Kaido and Big Mom. These pirates were way stronger, made a bigger name, and very often kept huge lands in the New World, which is the second half of the Grand Line.
The Great Pirate Era is characterized by a much greater degree of piracy across all the oceans of the world. With this surge, a lot of pirate crews have come into existence, each urged by various goals and philosophies. Some are searching for One Piece to gain fame and fortune, while others are using the era of turmoil to build empires.
Feeling the rising tide of piracy, the World Government and Marines clamped down ever more strongly on things. This would eventually create the Shichibukai system, under which the World Government sanctioned certain powerful pirates in return for their cooperation in helping quash other pirates. This complex political setup adds depth to the power struggles of the era.
The Great Pirate Era has also seen the advancement of technology in shipbuilding and navigation. Improvements in the log pose and eternal pose have helped pirates to further sail through the treacherous waters of the Grand Line. This helped even more pirates explore other areas of the world, which were previously inaccessible.
Among the most influential factors, the Great Pirate Era changed world politics and broke the balance of powers. The mighty pirate crews confronted the authority of the World Government with endless conflicts and a web of alliances. This political instability lies at the heart of the One Piece narrative since it supplies the context wherein many of the major story arcs in the series occur.
This age also marks a rediscovery of ancient weapons and renewed interest in the Void Century, a period of one hundred years of history that the World Government has been trying to erase. To that end, such a connection between the current age and ancient history adds more depth to One Piece world-building, suggesting that the Great Pirate Era could relate to greater cycles of history.
The Great Pirate Era is central to many adaptations of One Piece, even in the Netflix live-action series. These eras formed an important part of setting up the world and the character motivations.