Renaissance
Many argue that the ideas characterizing the Renaissance had their origin in late 13th-century Florence, in particular with the writings of Dante Alighieri (1265–1321) and Petrarch (1304–1374), as well as the paintings of Giotto di Bondone (1267–1337). Some writers date the Renaissance quite precisely; one proposed starting point is 1401, when the rival geniuses Lorenzo Ghiberti and Filippo Brunelleschi competed for the contract to build the bronze doors for the Baptistery of the Florence Cathedral (Ghiberti won). Others see more general competition between artists and polymaths such as Brunelleschi, Ghiberti, Donatello, and Masaccio for artistic commissions as sparking the creativity of the Renaissance. Yet it remains much debated why the Renaissance began in Italy, and why it began when it did. Accordingly, several theories have been put forward to explain its origins.
Harlem Renaissance
The Harlem Renaissance grew out of the changes that had taken place in the African-American community since the abolition of slavery, as the expansion of communities in the North. These accelerated as a consequence of World War I and the great social and cultural changes in early 20th-century United States. Industrialization was attracting people to cities from rural areas and gave rise to a new mass culture. Contributing factors leading to the Harlem Renaissance were the Great Migration of African Americans to northern cities, which concentrated ambitious people in places where they could encourage each other, and the First World War, which had created new industrial work opportunities for tens of thousands of people. Factors leading to the decline of this era include the Great Depression.