When did Mercury get its craters?

Mercury's craters primarily formed during the early history of the solar system, around 4.5 billion years ago, during a period known as the Late Heavy Bombardment. This era involved intense asteroid and comet impacts that pockmarked the surfaces of rocky bodies, including Mercury. As the planet's surface cooled and solidified, these impacts created the numerous craters we observe today. Although some cratering may have occurred later, the majority dates back to this early period.