Would you pls tell me whether this paragraph correct in English? (1.3)?

"The epigraph is in three paragraphs. The first is about the myths and legends of the founding of the Kingdom of Korea; the second is about the military life of King Haotai, fighting east and west and enlarging the territory; the third is about the guarding of the tomb. In 427A.D, the Koreans had moved their capital to P'yongyang and Ji’an city has lost its importance as the political, economical and military center and began to decline. After the fall of kingdom of Korea in 668 A.D., the monument of King Haotai was forgotten by history. After so many years of researching, this monument has become a special subject internationally, and the upsurges appear one after another."