roku

Roku is the genitive of rok, year, and is abbreviated r. In a written-out date it comes before or after the year words, as tysiąc osiemset sześćdziesiątego drugiego roku, in the year one thousand eight hundred sixty-second.

Only the last part of the year is an ordinal in the genitive, ending in -ego: in tysiąc osiemset sześćdziesiątego drugiego, the words for sixty-second are ordinals, while tysiąc osiemset, one thousand eight hundred, does not change. Roku pańskiego means in the year of the Lord, and roku przeszłego means of the previous year, which can move a date into the year before the record was written.