Simplify the following text for a Grade 7 native English-speaking person.
Original: It was during this long period though that there would emerge three individuals who would unite Japan under one rule ; they were Oda Nobunaga , Toyotomi Hideyoshi , and Tokugawa Ieyasu .
Simplified: They were Oda Nobunaga , Toyotomi Hideyoshi , and Tokugawa Ieyasu .