Richard III died in the thick of battle after losing his helmet and coming under a hail of blows from vicious medieval weapons, new research has shown. Detailed scans of the king's bones show that he sustained 11 wounds at or near the time of his death, nine of them to the skull.

The blows to the head were clearly inflicted in battle and suggest that he was not wearing his helmet.

There was another potentially fatal injury to the pelvis that may have been inflicted after death.

Professor Guy Rutty, from the University of Leicester, said: "The most likely injuries to have caused the king's death are the two to the inferior aspect of the skull – a large sharp force trauma possibly from a sword or staff weapon, such as a halberd or bill, and a penetrating injury from the tip of an edged weapon.

"Richard's head injuries are consistent with some near-contemporary accounts of the battle, which suggest that Richard abandoned his horse after it became stuck in a mire and was killed while fighting his enemies."

Richard III, the last English monarch to die fighting, perished at the Battle of Bosworth in 1485. It was the last significant battle of the Wars of the Roses, the civil war between the Houses of Lancaster and York, and paved the way for the Tudor dynasty.

Scientists and historians have been studying the king's remains since his skeleton was found under a car park in Leicester.

Evidence suggests he was not the hunchbacked, deformed monstrosity depicted by William Shakespeare.

Experts now know he had a bent spine with a "well balanced curve" that could easily have been concealed by clothing and would not have affected his prowess in battle. He probably did not walk with a limp.

The latest research, published in The Lancet medical journal's online edition, involved whole body CT (computed tomography) X-ray scans and micro-CT imaging.

Marks left on the bones by weapons were also analysed.

The serious injury to the pelvis should have been prevented by Richard's armour, according to the researchers. They speculate that it might have been inflicted after death, with the armour removed.

Co-author Professor Sarah Hainsworth, also from the University of Leicester, said: "Richard's injuries represent a sustained attack or an attack by several assailants with weapons from the later medieval period.

"The wounds to the skull suggest that he was not wearing a helmet, and the absence of defensive wounds on his arms and hands indicate that he was otherwise still armoured at the time of his death."

Commenting on the study, Dr Heather Bonney from the Natural History Museum in London said the research provided a "compelling account" of the way Richard III met his death.

She added: "Wherever his remains are again laid to rest, I am sure that Richard III will continue to divide opinion fiercely for centuries to come."