Simplify the following text for a Grade 6 native English-speaking person.
Original: From its invention in 1656 by Christiaan Huygens until the 1930s , the pendulum clock was the world 's most precise timekeeper , accounting for its widespread use .
Simplified: It was invented in 1656 by Christiaan Huygens . From the year 1656 until the 1930s , the pendulum clock was the world 's most accurate way of keeping time .