Vytautas wanted to control as much land as possible in the east, following Algirdas's goals.

Poland-Lithuania became known as a great power in Europe, and Vytautas gained much respect.

As a result of the Peace of Thorn of 1411, Vytautas received Samogitia for his lifetime. This pragmatic approach, rooted in survival against external threats, subdued internal fragmentation by 1400, though boyar autonomy persisted in local governance.^[4]Christianization, formally initiated in 1387 under Jogaila with elite baptisms and destruction of some sacred groves, advanced superficially under Vytautas post-1392, driven by diplomatic imperatives to neutralize Teutonic crusade pretexts rather than doctrinal zeal.

But because the land of Samogitia is lower than the land of Lithuania, it is called Samogitia, which in Lithuanian means 'lower land' [ Žemaitija ]. He conquered Smolensk in 1404 and waged a war in 1406-1408 against Muscovy, ending in peace at Ugra. Early awareness of threats from the Teutonic Order's crusading zeal and Moscow's growing Orthodox influence reinforced a realist outlook, prioritizing territorial integrity and familial dominance.^[8]

Initial Rule in Grodno and Lutsk

Vytautas received the principality of Grodno from his father Kęstutis around 1370, administering it until 1382 as an appanage within the Grand Duchy of Lithuania.^[4]Grodno's location on the western frontier necessitated oversight of border defenses against frequent Teutonic Knight raids, fostering Vytautas's initial expertise in military organization and regional governance under the oversight of the grand ducal court.,%20OCR.pdf) In 1387–1389, during the early phases of the Lithuanian civil war following Jogaila's accession to the Polish throne, Vytautas asserted control over Lutsk in Volhynia after the death of Liubartas in 1385, incorporating the area into his holdings amid alliances with local Rus' princes.^[9] This brief tenure highlighted his tactical adaptability in exploiting power vacuums and forging temporary pacts, while exposing him to the Orthodox religious and cultural dynamics of Rus' territories, which would influence his later eastern policies.,%20OCR.pdf) Lutsk's administration under Vytautas involved balancing Lithuanian authority with local Orthodox elites, demonstrating limited but effective autonomy outside Vilnius's direct control.

Rise to Power

Conflict with Jogaila and Early Rebellions (1377–1384)

Upon the death of Grand DukeAlgirdas on 30 May 1377, his son Jogaila assumed the position of Grand Duke of Lithuania, initially with the acquiescence of his uncle Kęstutis, who controlled Trakai and Samogitia and had co-ruled effectively with Algirdas.^[10][11] This arrangement reflected the flexible, non-hereditary succession norms among pagan Lithuanian dukes, where power was maintained through alliances and military strength rather than strict primogeniture, often leading to fraternal or avuncular power-sharing that masked underlying rivalries.^[10]Jogaila's early rule involved secretive diplomacy with the Teutonic Knights, culminating in the Treaty of Dovydiškės on 31 May 1380, which pledged mutual non-aggression but explicitly excluded Kęstutis's territories in Samogitia and along the Nevėžis River, exposing them to Teutonic raids and signaling Jogaila's intent to consolidate power by undermining his uncle.^[10]Kęstutis, informed of these intrigues by November 1381 amid intensified Teutonic incursions into Samogitia—which resulted in the loss of several border strongholds—mobilized forces, seized Vilnius, and declared himself Grand Duke, briefly imprisoning Jogaila and restoring a semblance of the prior diarchy while Vytautas, Kęstutis's son and heir to Trakai, supported these efforts through military actions in the eastern provinces.^[10][12]Jogaila escaped captivity and, with support from Vilnius boyars and Ruthenian vassals, recaptured the capital on 12 June 1382, forcing Vytautas to retreat to Grodno; this reversal fragmented Kęstutis's holdings, with Teutonic forces exploiting the chaos to seize additional Samogitian lands, including up to 20 fortified outposts by mid-1382.^[10] On 3 August 1382, under pretext of truce negotiations near Trakai, Jogaila arrested Kęstutis and Vytautas; Kęstutis was transported to Kreva Castle and strangled or otherwise killed on 8 August, an act attributed by contemporary accounts to Jogaila's orders or those of his mother Uliana, exemplifying the ruthless elimination of rivals in Lithuanian dynastic contests where oaths held little binding force absent enforcement.^[10][12][11] Vytautas, imprisoned in Vilnius, faced similar threats but escaped in late 1383, initiating raids into Lithuanian territories loyal to Jogaila, though these yielded only temporary disruptions amid ongoing pagan reluctance to accept Jogaila's overtures toward external powers that risked vassalage or conversion pressures.^[10][12]

Exile, Alliance with Teutonic Knights, and Return (1385–1392)

In late 1383, following his escape from imprisonment in Kreva after Kęstutis's murder, Vytautas sought refuge with the Teutonic Order at Marienburg and received command of the New Marienburg fortress, marking the onset of his strategic dependence on the crusading order to reclaim Lithuanian territories from Jogaila.^[10] By 1385, amid ongoing border skirmishes and failed initial incursions into Lithuania—such as the unsuccessful bid to hold Trakai—Vytautas deepened this alliance, providing the Order with intelligence and pledges of land cessions in exchange for military backing, a pact driven by his ambition to supplant Jogaila rather than any shared ideological opposition to paganism, given the Order's explicit crusading aims against Lithuania itself.^[10] This collaboration persisted through periods of dormancy, underscoring Vytautas's calculated exploitation of the Knights' resources for personal gain over fraternal or cultural ties to Jogaila's regime.Renewed hostilities erupted in 1389 when Vytautas, after a failed independent assault on Vilnius, dispatched hostages including his brother Zigmantas to the Teutons, formalizing support via the Treaty of Königsberg in early 1390 and enabling joint operations that bypassed religious pretenses in favor of territorial conquest.^[13] In summer 1390, Vytautas personally led Teutonic forces in a brutal raid on Vilnius, ravaging the outskirts, decimating defenders at the Crooked Castle, and compelling survivors to scatter, an action that inflicted severe damage on Jogaila's capital but yielded no full capture, highlighting the alliance's tactical efficacy despite the Order's ulterior motives to annex Lithuanian lands.^[13] By 1391, this pressure, combined with Vytautas's cultivation of internal dissent, prompted surrenders such as at Grodno, eroding Jogaila's control without necessitating total reliance on foreign crusaders, thus revealing the pact as a pragmatic lever for power consolidation rather than an act of existential desperation.^[10]As Lithuanian nobles increasingly backed Vytautas amid war weariness, he pivoted in 1392, negotiating directly with Jogaila at Astrava (Ostrów) on August 4, where the Ostrów Agreement granted him the grand ducal title and de facto autonomy in Lithuania while nominally affirming Jogaila's suzerainty as supreme duke, effectively nullifying Teutonic claims and prior concessions like Samogitian territories promised in the Salynas arrangements.^[10] This abrupt betrayal of the Knights—abandoning alliances forged just two years prior—exemplified Vytautas's realpolitik, prioritizing dynastic restoration through kin reconciliation over loyalty to opportunistic Christian aggressors, a maneuver that stabilized his rule without ceding permanent sovereignty to external powers.^[10] The agreement's success stemmed from Vytautas's amassed domestic leverage, not Teutonic goodwill, affirming his agency in navigating pagan Lithuania's precarious geopolitics.

Consolidation as Grand Duke

Internal Stabilization and Christianization (1392–1400)

Upon securing his position as Grand Duke through the Union of Vilnius and Radom in 1392, Vytautas prioritized internal consolidation by cultivating loyalty among the boyars, the powerful Lithuanian nobility, via strategic land grants in the Ruthenian territories and inclusion in advisory councils known as radas.