Early games of football in Britain were played with blown-up animal bladders. These tended to burst and eventually most ball games played during the Middle Ages used a more solid ball. According to one historian of this period the ball was "usually a leather covering filled with cork shavings or a similar material."
According to George Owen (c. 1550) in Wales football was slightly different from the game played in England: "There is a round ball prepared... so that a man may hold it in his hand... The ball is made of wood and boiled in tallow to make it slippery and hard to hold."
In most of Europe the ball continued to be an inflated animal bladder. In 1801 Joseph Strutt described the game of football in his book, The Sports and Pastimes of the People of England: "The ball, which is commonly made of a blown bladder, and cased with leather, is delivered in the midst of the ground, and the object of each party is to drive it through the goal of their antagonists, which being achieved the game is won."
In the early part of the 19th century footballs were leather-covered bladders. There were experiments with balls made of natural rubber but they bounced too high to be used in football matches. In 1830 Charles Macintosh discovered a way of producing thin rubber sheets. This enabled the production of inflatable rubber bladders for leather footballs.
In 1855 Charles Goodyear, his rubber-covered ball, coated with other materials, won a gold medal at the Paris Exposition Universelle. Although taken up by tennis and golf, the Goodyear ball was ignored by most football clubs.
The Football Association decided in 1872 that the football should be spherical with a circumference of 68 centimetres. It also had to be cased in leather and had to be weighed between 453 and 396 grams at the start of a game. As pointed out by The Encyclopedia of British Football: "On wet days the ball grew increasingly heavy as the leather soaked up large amounts of liquid. This, together with the lacing that protected the valve of the bladder, made heading the ball not only unpleasant but also painful and dangerous."
A large number of football players in the past have suffered long-term brain damage because of repeated heading of a heavy, wet ball. Stan Cullis, the Wolves and England centre-half was knocked unconscious during a game against Everton in the 1938-39 season. He suffered severe concussion that required intensive medical care. His doctors warned him that another serious concussion could kill him. A couple of years later a tremendous shot hit him in the face. Once again he suffered from severe concussion and was on the danger list for five days. He was warned by a doctor that because of his previous head injuries, even heading a heavy leather football could prove fatal and despite now being England's captain, Cullis decided to retire from playing football. In his later years, Cullis, like many footballers from this period, suffered from dementia. In 2002 a coroner said it was likely that the death of former West Bromwich Albion centre-forward, Jeff Astle, had been caused by "repeated small traumas to the brain".
Research carried out by D. R. Williams in 2002 concluded that repetitive mild head trauma over the course of an amateur and professional footballer's career may increase an individual's risk of developing dementia in later life. Former players who have suffered from this disease include Joe Mercer and Bob Paisley.
In the 1970s leather footballs were coated with a special polyurethane preparation, which eliminated water absorption during games. Footballs used today combine a latex bladder with an outer casing made from synthetic leather.
Most modern footballs are stitched from 32 panels of waterproofed leather or plastic: 12 regular pentagons and 20 regular hexagons. The 2006 FIFA World Cup Tournament used the 14-panel Adidas ball. The company have provided the official match balls for the tournament since 1970, and is a "thermally bonded" machine-pressed ball, rather than a traditionally stitched one.
There is a round ball prepared... so that a man may hold it in his hand... The ball is made of wood and boiled in tallow to make it slippery and hard to hold... The ball is called a knappan, and one of the company hurls it into the air... He that gets the ball hurls it towards the goal... the knappan is tossed backwards and forwards... It is a strange sight to see a thousand or fifteen hundred men chasing after the knappan... The gamesters return home from this play with broken heads, black faces, bruised bodies and lame legs... Yet they laugh and joke and tell stories about how they broke their heads... without grudge or hatred."
When a match at football is made, two parties, each containing an equal number of competitors, take the field, and stand between two goals, placed at the distance of eighty or an hundred yards the one from the other. The goal is usually made with two sticks driven into the ground, about two or three feet apart. The ball, which is commonly made of a blown bladder, and cased with leather, is delivered in the midst of the ground, and the object of each party is to drive it through the goal of their antagonists, which being achieved the game is won. The abilities of the performers are best displayed in attacking and defending the goals; and hence the pastime was more frequently called a goal at football than a game at football. When the exercise becomes exceeding violent, the players kick each other's shins without the least ceremony, and some of them are overthrown at the hazard of their limbs.