Supreme Court Senior Associate Justice Antonio Carpio has once again sounded the alarm on China’s continuing activities in the West Philippine Sea.

China, he said, is not just building artificial islands at seven reefs that are all within the Philippines’ exclusive economic zone as defined and recognized by the United Nations Convention on the Law of the Sea, to which both countries are signatories. The fortifications being made are at the expense of 10 other reefs within the contested area, which are being dredged to provide filling material for the seven reefs that China has appropriated for itself, despite competing claims not only by

the Philippines but also by Vietnam, Malaysia, Brunei and Taiwan.

Carpio’s earlier research into and survey of 60 ancient maps, the oldest of which dates back to 1136 under

China’s Nan Song Dynasty, have persuasively debunked China’s claim of “historical ownership” over nearly 90 percent of the South China Sea based on its so-called “nine-dash line.” That demarcation would have brought China’s maritime border suffocatingly close to a long stretch of the Philippines’ coastline—from Yamin Island in northern Batanes to Balabac Island in southern Palawan, as Carpio has pointed out.

But, as his research into ancient cartography shows, none of the maps ever indicated that the Spratly Islands and Scarborough Shoal were ever part of Chinese territory. In fact, another map not part of Carpio’s survey appears to provide conclusive proof that Scarborough Shoal, then called “Panacot,” was already part of the Philippine domain some 300 years ago. The Murillo Velarde map, a certified true copy of which was recently acquired by businessman Mel Velarde through auction at Sotheby’s in London, includes Scarborough or Panacot in what it presents as a “A Hydrographical and Corographical Chart of the Philippine Islands,” circa 1734.