Captain John Ratcliffe was the English commander of the Discovery ship that reached the state of Virginia, from England, on 26 April, 1607. The Discovery had a crew of 21 men and was the smallest of the three ships in the colonial expedition. The other two were the Susan Constant and the Godspeed. John Ratcliffe was one of the earliest English Colonial settlers and colony leaders in Jamestown, Virginia. Jamestown was founded on 13 May, 1607.

John Ratcliffe was said to use the alias of John Sickelmore, but this was never confirmed. Actually, nothing concrete seems to be documented about his early life, under either surname. John Ratcliffe was elected president of the governing colony in September, 1607 and Captain John Smith was elected to those duties in 1608. The colony John Ratcliffe led was called Fort Algernon and was located at Fort Comfort. Captain James Davis led Fort Algernon after John Ratcliffe's horrible death in September, 1609.

The details of Ratcliffe's death were so unfortunate that he was remembered as The Luckless Captain Ratcliffe. It was reported that he was killed during his search for food and trade deals along the Pamunkey River. Apparently, John Ratcliffe had accused the Native Americans of not trading fairly. Pocahontas' father, Chief Powhatan, was said to have ordered Ratcliffe's death. This was at least the second time as Pocahontas had already convinced her father not to have John Ratcliffe killed when Powhatan wanted Ratcliffe to be clubbed to death with stone clubs.

John Ratcliffe was reported to have been killed in September 1609 by the direct order of Powhatan. Ratcliffe was said to have been tied to a tree with boiling water placed at his feet. The women of the tribe were thought to have been the ones to scrape off Ratcliffe's skin with sharp mussel shells and then throw his face into the fire.