Władysław I the Elbow-high of Kujawy, however, as he had two older half-brothers from Casimir’s second marriage to Constance of Wrocław: Leszek II the Black ("Leszek Czarny") and Ziemomysł. He was named after his uncle, his mother's brother Władysław, Duke of Opole. Already in contemporary sources he was nicknamed ""Łokietek"", a diminutive of the word "łokieć". It translates as "elbow" or "ell" – a medieval unit of measure similar to a cubit, as in "elbow-high". The origin of this nickname, as resulting from Władysław’s short stature, was explained only in the 15th century by historian Jan Dlugosz. In 1267, when Władysław the Elbow-high was
Ancient Roman units of measurement Ancient Roman units of measurement The ancient Roman units of measurement were largely built on the Hellenic system, which in turn was built upon Egyptian and Mesopotamian influences. The Roman units were comparatively consistent and well documented. The basic unit of Roman linear measurement was the "pes" or Roman foot (plural: "pedes"). Investigation of its relation to the English foot goes back at least to 1647, when John Greaves published his "Discourse on the Romane foot". Greaves visited Rome in 1639, and measured, among other things, the foot measure on the tomb of Titus Statilius Aper, that on the statue