The history of painting reaches back in time to artifacts from pre-historic humans, and spans all cultures. It represents a continuous, though periodically disrupted, tradition from Antiquity. Across cultures, and spanning continents and millennia, the history of painting is an ongoing river of creativity, that continues into the 21st century. Until the early 20th century it relied primarily on representational, religious and classical motifs, after which time more purely abstract and conceptual approaches gained favor.