In season eight, Latin Grammy Award-nominated singersongwriter and record producer Kara DioGuardi was added as a fourth judge. She stayed for two seasons and left the show before season ten. Paula Abdul left the show before season nine after failing to agree terms with the show producers. Emmy Award-winning talk show host Ellen DeGeneres replaced Paula Abdul for that season, but left after just one season. On January 11, 2010, Simon Cowell announced that he was leaving the show to pursue introducing the American version of his show The X Factor to the USA for 2011. Jennifer Lopez and Steven Tyler joined the judging panel in season ten, but both left after two seasons. They were replaced by three new judges, Mariah Carey, Nicki Minaj and Keith Urban, who joined Randy Jackson in season 12. However both Carey and Minaj left after one season, and Randy Jackson also announced that he would depart the show after twelve seasons as a judge but would return as a mentor. Urban is the only judge from season 12 to return in season 13. He was joined by previous judge Jennifer Lopez and former mentor Harry Connick, Jr.. Lopez, Urban and Connick, Jr. all returned as judges for the show's fourteenth and fifteenth seasons.
When did Steven Tyler become a judge?
season ten

Boston has an area of 89.6 square miles (232.1 km2)48.4 square miles (125.4 km2) (54.0%) of land and 41.2 square miles (106.7 km2) (46.0%) of water. The city's official elevation, as measured at Logan International Airport, is 19 ft (5.8 m) above sea level. The highest point in Boston is Bellevue Hill at 330 feet (100 m) above sea level, and the lowest point is at sea level. Situated onshore of the Atlantic Ocean, Boston is the only state capital in the contiguous United States with an oceanic coastline.
Boston is the only state capital in the contiguous US to have what type of coastline?
oceanic coastline

The dates are generalizations, since the periods and eras overlap and the categories are somewhat arbitrary, to the point that some authorities reverse terminologies and refer to a common practice "era" comprising baroque, classical, and romantic "periods". For example, the use of counterpoint and fugue, which is considered characteristic of the Baroque era (or period), was continued by Haydn, who is classified as typical of the Classical era. Beethoven, who is often described as a founder of the Romantic era, and Brahms, who is classified as Romantic, also used counterpoint and fugue, but other characteristics of their music define their era.
Some authorities reverse terminologies to refer to the common practice period as a what?
era