evidence: By the Song dynasty, China maintained that it was naming and claiming territory in the island chains it calls Nansha (the Spratly Islands) and Xisha (the Paracel Islands). [...] In the 20 years since, China has reinforced the map with more concrete signs of its claim – building on rocks and islets and expanding its military facilities on these man-made outposts. It has also backed up its claims with ships from its coast guard, maritime militia and fishing fleets. [...] "In the 1970s and 1980s, China took over control of much of the Paracel Islands in the northern SCS [South China Sea] and Johnson South Reef in the Spratly Islands in the southeast quadrant of the SCS, both in Vietnam’s EEZ," the United States department of defence wrote.