By the year 1500, a wooden frame racquet strung with sheep gut was in common use, as was a cork-cored ball weighing around three ounces. The early tennis courts were quite different from the modern "lawn tennis" court most of us are used to. The early game matured into what is now called "real tennis," and England's Hampton Court, built in 1625, is still used today. Only a handful of such courts remain. It's a narrow, indoor court where the ball is played off walls that include a number of openings and oddly angled surfaces toward which the players aim for various strategic purposes. The net is five feet high on the ends, but three feet in the middle, creating a pronounced droop.
1850 - A Good Year
The game's popularity dwindled almost to zero during the 1700s, but in 1850, Charles Goodyear invented a vulcanization process for rubber, and during the 1850s, players began to experiment with using the bouncier rubber balls outdoors on grass. An outdoor game was, of course, completely different from an indoor game played off walls, so several new sets of rules were formulated.
1874 - The Birth of Modern Tennis
In 1874, Major Walter C. Wingfield patented in London the equipment and rules for a game fairly similar to modern tennis. In the same year, the first courts appeared in the United States. By the following year, equipment sets had been sold for use in Russia, India, Canada, and China.
Croquet was highly popular at this time, and the smooth croquet courts proved readily adaptable for tennis. Wingfield's original court had the shape of an hourglass, narrowest at the net, and it was shorter than the modern court. His rules were subjected to considerable criticism, and he revised them in 1875, but he soon left the further development of the game to others.
In 1877, the All England Club held the first Wimbledon tournament, and its tournament committee came up with a rectangular court and a set of rules that are essentially the game we know today. The net was still five feet high at the sides, a carryover from the game's indoor ancestor, and the service boxes were 26 feet deep, but by 1882, the specifications had evolved to their current form.