Question

Which leader extended the persian empire into europe to become the largest empire the world has yet seen

Answer 1

Cyrus the Great, who ruled from 600 to 572 BCE, created the Achaemenid Empire (First Persian Empire).

Around 500 BCE, it became the largest empire the world had yet seen. Darius I, aka Darius the Great (ruled 522-486 BCE), was in charge then.

Larger empires came after it, the largest to date being the British Empire during the early 1900s-ish.