on the pilgrimage to gniezno, emperor otto iii was received by bolesław at the polish border on the bóbr river near małomice. bishop unger of poznań escorted him to gniezno. between the 7th and 15th of march otto invested bolesław with the titles "frater et cooperator imperii" ("brother and partner of the empire") and "populi romani amicus et socius" as rendered in the 1115 "gesta principum polonorum" by the kraków chronicler gallus anonymus, the first author of polish history. whether the act implemented an elevation of bolesław to the status of "king" has not been conclusively established. in any case, bolesław had himself crowned king of poland at gniezno cathedral in 1025.