According to older historiography, based on the information of Vasily Tatishchev, 18th-century Russian historian, Leszek fought against Prince Volodar of Minsk, who in 1180 captured Brest, which belonged to his brother-in-law, Vasilko Iaropolkovich.
Menurut historiografi yang lebih tua, berdasarkan informasi dari Vasily Tatishchev, sejarahwan Rusia abad ke-18, Leszek bertempur melawan Pangeran Volodar dari Minsk, yang pada tahun 1180 merebut Brest, ang merupakan saudara iparnya, Vasilko Iaropolkovich.