Though the name is Polish as spelt the origin may be more complicated. There is also a German surname, Peschat, which looks like the same name. A list of East Prussian names online gives the ending -at as a Baltic diminutive. Some examples from the name list are Adomat, from Adam; Endruschat, from Andrew; and Peterat from Peter. Not all -at names are from personal names, the list contains some said to be from place names, eg. Meinekat and Rudat. Others appear to be nicknames; Kassat from the Latvian Kaze, 'goat', and Jotzat from the Lithuanian juodas, 'black'. East Prussia was part of the kingdom of Prussia, which also took in traditional Polish territory. The names reflect the mixture of languages and influences affecting the population and its names; German, Slavic, and the Baltic languages, Old Prussian, Lithuanian and Latvian.