CREATE TABLE table_26516 ("Co-king" TEXT, "Relationship to Monarch" TEXT, "Crowned" TEXT, "Co-kingship ceased" TEXT, "Reason" TEXT, "Monarch" TEXT)

Name the crownded for 17 september 1025
SELECT "Crowned" FROM table_26516 WHERE "Co-kingship ceased" = '17 September 1025'
SELECT "Crowned" FROM "table_26516" WHERE "Co-kingship ceased" = '17 September 1025'