Ballet is often the dance style that springs to mind when thinking of European/Western dance. It has a long history stretching back to the Italian Renaissance in the 15th century where it started as entertainment for aristocrats.
Ballet is a dance form that incorporates many codified steps and movements that have evolved over centuries. It uses body movements, music, and stage décor to communicate a narrative or more abstract elements. Different styles and techniques have emerged over time often associated with geographic regions like France, Italy or Russia, or with certain teachers and choreographers.
The romantic ballet of the early to mid 19th century saw women become more central to the dance form. This was also the time that introduced dancing on tiptoe (en pointe) and the early tutu which was a calf-length, flowy tulle skirt. Everything about this time in ballet had a more ethereal aesthetic.
Classical ballet of the late 19th and early 20th century continued to see the emphasis on traditional form with fluid, graceful movements, long lines and the correct turn-out of legs and feet. With better pointe shoes, ballerinas continued to be the focus of most dances with increasingly complicated footwork leading to shorter tutus to highlight the technique of the dancers.
Neo-classical ballet of the early to mid 20th century rebelled somewhat against the form, styles and theatricality of the classical ballet. Ballet from this time tends to be more abstract, usually with an emphasis on strong physicality and distorted movement, and often with little on the stage other than the dancers.
Contemporary ballet style continues to evolve but can track its beginnings to the mid-20th century. While still grounded in classical ballet training and form, it borrows from many other dance styles, can be performed with bare feet or in pointe shoes, with turned in legs and feet, and involves even more athleticism, strength and speed than in the past. In fact, it may have more in common with contemporary dance than classical ballet.