But in the end they were done for by ... make-up.
Researchers have found that children of the samurai class suffered severe lead poisoning because of the cosmetics used by their mothers and grew up deformed, disabled and backward.
These handicaps left them unable to cope with political crises, leading to instability that led to the eventual downfall of their feudal system, the study claims.
Tamiji Nakashima of Japan's University of Occupational and Environmental Health studied the bones of Samurai children and adults to discover their cause of death.
Based on chemical and X-ray analysis, the bones of the children in the study contained levels of lead dozens of times higher than both the male and female adults, the researchers told Germany‘s Der Spiegel magazine.
'The median value for the children three years of age and under was over fifty times higher than that of their mothers,' it said.
White facial powder used by the women was the cause. 'During the Edo period, cosmetics became popular and the vogue was usually introduced by actors, courtesans and geisha, through prints and popular literature, and by beauticians who helped establish fashions,' the researchers said.
'The white face powders used in those days were made from mercury chloride and white lead. Lead levels in the bones of adult women were roughly double those of men in the study.
'And their breast milk was likely highly-contaminated, leading to the very severe lead levels in the youngest children.'The high lead concentrations in the samurai children of the Edo period may have left them intellectually incapable of dealing with the final political crisis between 1853–1867, resulting in the downfall of the Shogunate.'A ruling class afflicted with brain damage isn't a recipe for success. As samurai were the ruling class, severe political insecurity could develop when highly lead-contaminated samurai children grew up.'
According to the World Health Organisation, lead causes a variety of ill effects, and is particularly harmful to children. Too much lead damages the nervous and reproductive systems, causes high blood pressure and anaemia, and accumulates in the bones. It is especially harmful to the developing brains of foetuses and young children, with it interfering with the metabolism of calcium and Vitamin D and causing irreversible effects including learning disabilities, behavioural problems and mental retardation.
At very high levels lead poisoning causes convulsions, coma and, eventually, death.Dr Nakashima's team studied the bones of children who lived as far back as 400 years ago during Japan's Edo period, when the country was ruled by a series of shoguns who presided over a feudal system upheld by the Samurai caste.
After sampling the lead in their rib bones and taking X-rays of some of the youngsters' long arm and leg bones they found children with enough lead in their systems to cause severe intellectual impairment.
Those under three were the worst off, with a median level of 1,241 micrograms of lead per gram of bone - more than 120 times the level thought to cause neurological and behavioural problems. With global lead pollution much lower in the before the beginning of the industrial revolution, Dr Nakashima's researchers surmised that the contamination must have been caused by the make-up worn by women of the Samurai caste.
His study showed that the women of the era had far higher levels of lead in their bones than men, and this contamination was passed on to youngsters while nursing. Their analysis of the bones of those who didn't make it adulthood suggested that many who survived their childhood probably suffered from severe intellectual impairment, LiveScience reported.
'We assume that facial cosmetics were one of the main sources of lead exposure among the samurai class because they were luxuries at that time,' Dr Nakashima told LiveScience. 'The lower class people (farmers and fishermen) did not have the luxury of using cosmetics and the laws strictly prohibited [them] from using cosmetics because they were workers.'
Although lead poisoning was among the first known environmental hazards, from ancient times right up until relatively recently people were fond of its diverse uses and believed they could minimise the risk.Many believed that limiting exposure would limit the danger to health, without realising that everyday low-level exposure to it made them vulnerable to chronic lead poisoning.
The Romans used lead extensively in building aqueducts from about 500BC to 300AD, despite Julius Caesar's engineer Vitruvius reporting that 'water is much more wholesome from earthenware pipes'. It is even thought lead poisoning may have contributed to the decline of the Roman Empire.Throughout the Middle Ages, the metal continued to be widely used for a range of applications, but it wasn't until the Industrial Revolution that lead poisoning became common in the work setting.
The introduction of lead paint for residential use in the 19th century increased childhood exposure to lead; for millennia before this, most lead exposure had been occupational.Toxicity in children from lead paint was finally recognised in 1897 and France, Belgium, and Austria banned white lead interior paints in 1909; the League of Nations followed suit in 1922.
However, in the U.S., laws banning lead house paint were not passed until 1971, and it was phased out and not fully banned until 1978.The 20th century saw an increase in worldwide lead exposure levels due to the increased widespread use of the metal. From the Twenties, lead was added to petrol to improve its combustion and lead from exhaust fumes persists today in soil.
The levels found today in most people are orders of magnitude greater than those of pre-industrial society. Due to reductions of lead in products and the workplace, acute lead poisoning is rare in most countries today. However, low-level lead exposure is still common.