The article is an analysis of transport routes published in La description du Royaume de Poloigne by Blaise de Vigenère (1573). The book was a manual, as it were, intended for Henri de Valois and his court heading for the Polish-Lithuanian Commonwealth. In addition to its chorographic aspect, it also contained an analysis of the Commonwealth's political system, law and society. The descriptions of the main routes were very good, with the author presenting the roads leading from Paris and Vienna to Kraków, and then to Gdańsk and Vilnius, Polotsk, Orsha and as far as Moscow. On their basis I have been able to establish the difference in units of distance between the various countries (one lieues in France corresponded to 4.75 km, 5.1 km in the Moscow Empire, 7.5 km in the Polish-Lithuanian Commonwealth and 8.8 km in the German Empire). Blaise de Vigenère suggested to his reader the borders of states and provinces, which was to be an indication of a possibility of applying various measures of distance. Calculations demonstrates that miles in the Crown were slightly shorter than those in the Grand Duchy of Lithuania (7.3 to 7.69 km); the uniqueness of Polotsk is also evident -- as a result of very complicated routes miles in the region were extremely short (about 5 km). The averaged mile length in the Polish-Lithuanian Commonwealth was 7.5 km. 42.5 km/day. It was quicker to travel along the main route from Vilnius to Kraków (55 km/day). Barely half of this speed was achieved by carts laden with goods and by people travelling on foot (25 km/day). A skilful rider, changing horses along the way, without any cart or unnecessary load could achieve a much higher speed. Founded by Sigismund II Augustus in 1558, the postal service linking Kraków with Venice was to have reached the speed of 92.9 km/day. In reality it was able to cover only about 62 km/day. Journeys in large groups of carts, with extended transport columns, were much slower. The average speed achieved by the travelling court of Stephen Báthory was 30-35 km/day. Polish-Lithuanian armies (but not individual units) travelled even more slowly, at 7-27.5 km/day. [ABSTRACT FROM AUTHOR]