Lechia is the mythological name for Poland, stemming from the word Lech (which is also a common first name).
According to legend, the name derives from the first ruler of Poland, Lech. It is also the derivation for the term Lechitic languages.
To answer your first question yes, Hermes was (among other things) a god of thievery.
An excerpt from the Hermes Theoi page
HERMES was the Olympian god of herds and flocks, travellers and hospitality, roads and trade, thievery and cunning, heralds and diplomacy, language and writing, athletic contests and gymnasiums, astronomy and astrology. He was the ...