Nicholas I (Latin: Nicolaus, Danish: Niels, German: Nikolaus) (died 1233) was Bishop of Schleswig between 1209 and 1233. Since 1192 he de facto, though not consecrated, officiated during the flight and following royal captivity of his predecessor Bishop Valdemar (1193–1206). After Valdemar's papal deposition in 1208 Nicholas was finally consecrated as bishop in 1209. Since 1214 Nicholas also served as Chancellor of Denmark (i.e. about prime minister) until his death.