Casimir inherited a kingdom weakened by war and made it prosperous and wealthy. He reformed the Polish army and doubled the size of the kingdom.
He reformed the judicial system and introduced a legal code, gaining the title “the Polish Justinian”. Casimir built extensively and founded the University of Kraków, the oldest Polish university. He also confirmed privileges and protections previously granted to Jews and encouraged them to settle in Poland in great numbers.
King Casimir III the Great (1333–1370) erected most of the once formidable fortresses to protect what was Poland’s western frontier, at the time perilously close to the country’s capital city, Krakow.
Later on the king’s castles passed into the hands of various aristocratic families, together with the adjacent land. New owners usually did their best to adapt the medieval fortresses.
As stately manor-houses and family nests through successive overhaul, expansion, refurbishment, renovation, etc. without compromising the defenses as long as possible. Nonetheless eventually the proud eagle-nest castles largely turned into picturesque ruins over the centuries.
The Trail of the Eagles’ Nests of south-western Poland, is a marked trail, named after a chain of 25 medieval castles which the trail passes by, between Częstochowa and Kraków. The Trail of the Eagles’ Nests was first marked by Kazimierz Sosnowski. Since 1980, much of the area has been designated a protected area known as the Eagle Nests Landscape Park.
The castles date mostly to the 14th century, and were constructed by the order of King of Poland Kazimierz the Great. They have been named the “Eagles’ Nests”, as most of them are located on large, tall rocks of the Polish Jura Chain featuring many limestone cliffs, monadnocks and valleys below. They were built along the 14th-century border of Lesser Poland with the province of Silesia, which at that time belonged to the Kingdom of Bohemia.
The Trail of the Eagles’ Nests is considered one of the best tourist trails in Poland, marked as No. 1 on the official list of most popular trails in the country. It encompasses all 25 castles and watchtowers, and is 163 kilometres (101 miles) long (the bicycle trail is 188 km (117 mi) long). Most of the sites can also be reached by bus.
The Eagles’ Nests castles, many of which survived only in the form of picturesque ruins, are perched high on the tallest rocks between Częstochowa and the former Polish capital Kraków. The castles were built to protect Kraków as well as important trading routes against the foreign invaders. Later, the castles passed on into the hands of various Polish aristocratic families.