Grand duke of Lithuania from 1345 to 1377, who doubled the duchy eastward into the Rus' lands, broke the Golden Horde's hold on Kiev at the Battle of Blue Waters, marched three times on Moscow, and ruled for thirty-two years alongside his brother Kęstutis without once fighting him.
Algirdas took power in 1345 with his brother Kęstutis by deposing a third brother, and the two then ruled together for thirty-two years in an arrangement that has few parallels in medieval Europe. Algirdas held Vilnius and the east; Kęstutis held Trakai, Samogitia and the war against the Teutonic Order in the west. Neither tried to remove the other.
Facing east, Algirdas roughly doubled the duchy. Bryansk, Chernihiv, Novhorod-Siverskyi, Podolia and finally Kiev came under Lithuanian rule, most decisively after his victory over three Tatar princes at the Battle of Blue Waters in 1362. Three times — in 1368, 1370 and 1372 — he marched on Moscow and burned its suburbs without taking the new stone Kremlin, and he died in 1377 a pagan, cremated with eighteen horses, having named his son Jogaila to succeed him over his elder brothers.
Born about 1296 — an estimate, not a recorded year — Algirdas was one of the seven sons among whom Gediminas distributed the duchies of the realm. His portion was Vitebsk, which came to him by marriage to Maria, daughter of its last prince, and he governed there for two decades before he ever ruled at Vilnius.
Those decades mattered more than his eventual accession. Vitebsk was an Orthodox Rus' town with its own law, its own church and its own boyars, and Algirdas spent his formative years as a pagan Lithuanian prince governing Slavic Christians by consent. The policy he later applied from the Baltic to the Dnieper was one he had already practised in a single principality.
Algirdas is the best example in this archive of a ruler whose reputation depends on which enemy is describing him. The Rus' chronicles, written by churchmen in the towns he attacked, are the fullest source and they are grudgingly admiring: a prince of great cunning who told nobody his plans, abstained from wine and mead, and moved so fast that his armies arrived before news of them. The Teutonic chroniclers, who mostly faced Kęstutis, barely describe him at all — which is itself evidence for how the brothers divided the work.
The Orthodox tradition also holds the darkest charge against him. Three of his courtiers, Anthony, John and Eustathios, were executed at Vilnius in 1347 for refusing to abandon Christian practice, and are venerated as the Vilnius Martyrs; whether Algirdas ordered it under pressure from the pagan priesthood or permitted it to appease them, the killings happened in his city and under his authority. Against that sits a long record of Orthodox churches built and Orthodox law confirmed across his conquests, including by his own two Orthodox wives.
His own religion was argued over almost immediately. Hermann von Wartberge and later Jan Długosz insist he remained a pagan to the end, and the cremation with eighteen horses at Maišiagala supports them; some Rus' accounts claim a deathbed baptism and monastic vows, and a few modern Russian historians have read him as an Orthodox ruler throughout. The likeliest reading is the least satisfying one: a pagan who found it useful to be unreadable, in a realm where most of his subjects were Christians of one confession or another.
Gediminas had left Vilnius to Jaunutis in 1341, and by 1345 Algirdas and Kęstutis judged him incapable of holding it. Their coup was coordinated and bloodless: Kęstutis seized Vilnius in winter and handed it to his elder brother, and Jaunutis, after a failed appeal to Moscow, was compensated with the duchy of Zaslawye. Algirdas became grand duke; Kęstutis received hereditary right in Trakai and the standing of a co-ruler rather than a subject.
What followed is the genuinely unusual part of the reign. For thirty-two years the two governed a single state from two capitals, dividing it along the line of the threat: Algirdas faced east and south against the Rus' principalities, Moscow and the Horde, while Kęstutis faced west against the Teutonic Order and the crusading raids into Samogitia. Treaties with the Order were negotiated by Kęstutis, campaigns on the Dnieper led by Algirdas, and each acted for both.
The arrangement survived because it was a division of labour rather than a partition of sovereignty — there was one grand duke, and Kęstutis never claimed to be him while his brother lived. It is best measured by what did not happen: no civil war between them in three decades, in a dynasty that fought itself bitterly in the generation before and the generation after. Within five years of Algirdas's death his son and Kęstutis were at war, and Kęstutis was dead.
The eastern expansion was steady rather than spectacular for most of the reign: Bryansk, Chernihiv, Novhorod-Siverskyi and the Podolian steppe came in by conquest, marriage and the placing of Gediminid princes on local thrones, usually with the existing law and church left untouched. Algirdas married twice into Rus' ruling houses — Maria of Vitebsk and then Uliana of Tver — and the second marriage drew him into the long struggle between Tver and Moscow that shaped the rest of his career.
The decisive blow fell on the Horde. In the autumn of 1362 Algirdas met the armies of three Tatar princes of the western Horde — Khachibey, Kutlubuga and Dmitry — at the Battle of Blue Waters on the Syniukha, a tributary of the Southern Bug, and destroyed them. The date is not entirely secure: the Rogozhsky chronicler, the earliest witness, places the campaign in 1363, and a minority of historians have questioned how large the engagement really was.
The consequences are not in doubt. Kiev passed under Lithuanian rule and Algirdas installed his son Volodymyr there; Podolia was taken; the Horde's authority over the lands between the Dnieper and the Dniester collapsed, and its western frontier pulled back toward the Crimea. It was the first serious reversal the Horde suffered in the Rus' lands, eighteen years before Kulikovo, and it made Lithuania a Black Sea power.
The Lithuanian–Muscovite war of 1368 to 1372 was fought over Tver, whose prince Mikhail was Algirdas's brother-in-law and was being steadily squeezed by Dmitry Ivanovich of Moscow. Algirdas answered the appeal and marched in November 1368, destroying a Muscovite covering force on the Trosna and reaching the city itself.
There he met the reason all three campaigns failed. Dmitry had replaced Moscow's oak walls with white stone in 1367, the year before, and the new fortifications held. Algirdas burned the posad and the surrounding country for three days and withdrew; he came again in 1370 with the same result, and a third time in 1372, when the two armies faced each other near Lyubutsk and made a truce instead of a battle.
The verdict on all three is mixed, and deliberately so: Algirdas never took Moscow and never intended to hold it, but he demonstrated that Lithuania could reach it at will, and the Treaty of Lyubutsk left Tver protected for the moment. The longer consequence went the other way. Moscow learned the value of stone walls and of the metropolitan's authority over the Orthodox of Lithuania, and the contest for the Rus' lands that Algirdas opened was one his successors gradually lost.