Leičiai (singular: leitis) were a distinct social group of the Lithuanian society in the early Grand Duchy of Lithuania subordinate to the Lithuanian ruler or the state itself. Leičiai were native to the Lietuva Land and formed the core of the Lithuanian society in the pre-state era and during the establishment of the state. Leičiai made up the majority of the military-economic staff of the state: they enforced state authority in the periphery, protected state borders, and performed various other war-related functions, such as breeding riding horses. By the 15th and 16th centuries, leičiai were in decline, already losing some of their functions and prestige, and they disappeared as a social class after the implementation of the Wallach Reform. According to the hypothesis brought forward by Lithuanian historian Artūras Dubonis and linguist Simas Karaliūnas, the name of Lithuania (Lietuva) derived from leičiai. Leičiai is an old ethnonym used by Latvians to denote the Lithuanians (leiši in Latvian) and was historically known to the Germans in the same sense. Opponents to the hypothesis which attempts to relate the words leitis, leičiai and Lietuva, claim that the form leičiai, leitis, with a diphthong -ei- instead of -ie-, is likely to be of Western Baltic origin. Leičiai service Leičiai were war-like servants of a ruler, the staff enforcing his authority. Their duties were likely war-related, among which possibly were breeding riding horses, providing roadmen, protecting state borders. They were a possession of the monarch, that is, subordinates to the state and not to nobles. The first mention of them in written sources is known from 1407, when Grand Duke Vytautas granted an estate and its staff, including leytey, to Manvydas, then an elder of Vilnius. Later Grand Dukes Alexander Jagiellon and Sigismund I the Old used to transfer royal estates to nobles for a temporary administration in exchange for cash, which was needed to finance continuous wars with the Grand Duchy of Moscow. These contracts are the major primary source on leičiai. Their name was rendered in various forms: leythey, leyty, leytten, litten, лейти, лейци, лейтеве, лойти, людей лейтъскихъ, etc. These forms are considered to be the same as in у Лейтахъ – in Leičiai (administrative area). By the 15th century, this social group and their services were in decline. For example, one leitis from volost of Eišiškės, in a 1514 litigation against a minor landowner over his patrimonial plot, said that he