Trịnh–Nguyễn War
Wanting to test Đào Duy Từ, the Nguyễn lord wore casual clothing and stood near a small door of Phú Xuân Palace when Đào Duy Từ first met him (these actions could be considered as a disdain by confucianist scholars during this time). Thereon Đào Duy Từ kept refusing to talk with Lord Nguyễn Phúc Nguyên until the lord opened the main gate of the palace and wore formal clothing. After a long meeting in which Đào Duy Từ discussed and gave advice about the current Trịnh–Nguyễn War, Lord Nguyễn Phúc Nguyên appeared to like Đào Duy Từ's ability and then he made Đào Duy Từ his advisor and a high ranking mandarin.