A museum in Fukuoka Prefecture in western Japan, has put on display objects from 13th-century sunken ships that were part of a Mongolian fleet that attempted to invade Japan.

The fleet is believed to have sunk in a storm off the island of Takashima in Nagasaki Prefecture, after the initial attack was repelled.

The display of 13 items began at the Fukuoka City Museum this month.

They include a weapon called “tetsuhau,” which contains gunpowder and pieces of iron. Mongolian soldiers are believed to have thrown it after lighting its fuse.

Also on display is a helmet weighing 2.8 kilograms. Historians say helmets of this era were round, not pointed at the top like older types.

The museum’s curator Horimoto Kazushige says he hopes the exhibit will help visitors know about the beginning and end of the two Mongolian invasions. He added that he hopes to show more objects if the ongoing archaeological work produces new discoveries.