LTViena iš svarbiausių XVI a. vidurio LDK politikos krypčių buvo Livonijos problemos sprendimas. 1557 m. Pasvalio sutartis galima laikyti pirmo etapo, įsitvirtinant Livonijoje, pabaiga, pamatu tolesnei įvykių raidai. Norint tinkamai įvertinti bendrą šio istorinio įvykio reikšmę ir svarbą visų pirma būtina išsiaiškinti proceso varomąsias jėgas, vidaus ir išorės veiksnius. Taigi pagrindinė šio straipsnio užduotis - atsakyti, ar tai buvo natūraliai, Lietuvos viduje pribrendęs siekimas, ar, priešingai, lemiamą vaidmenį čia turėjo Hohencolernų agitacija. Gausiausią publikuotų šaltinių, atspindinčių Livonijos ordino, Rygos arkivyskupystės ir kitų krašto politinių vienetų santykius su kaimyninėmis valstybėmis, tarp jų ir LDK, dalį sudaro XIX a. II pusėje daugiausia Livonijos vokiečių tyrinėtojų paskelbti Kenigsbergo, Stokholmo, Rygos bei Revelio archyvų ir bibliotekų dokumentai. Nagrinėjamai problemai aktualiausią medžiagą teikia Carlas Schirrenas, Karlas Eduardas Napiersky. Tarp Žygimanto Augusto ir Šv. Romos imperijos dėl LDK ir Livonijos santykių paaštrėjimo vykęs susirašinėjimas atsispindi Maciejaus Dogielio aktų rinkinyje [p. 285].
ENOne of the principal trends in the policy of the Grand Duchy Lithuania in the mid-sixteenth century was strengthening its influence in Livonia. The initial objective was to secure the safety of the northern Lithuanian borders and the freedom of trade during the conflict with Russia, and subsequently attempts were made to turn Livonia into an active military ally or to incorporate it into the state of Sigismundus Augustus. The Prussian Duke Albrecht also sought to acquire the Livonian territory of the Order of the Swordbearers as his fief. As a vassal of Sigismundus Augustus he intended to set up a secular state there and to unite it with Prussia. He had a plan to establish a Hohenzollern state, protracting from the river Vistula to the Daugava and associated with Brandenburg and Mecklenburg by close ties of kinship. Albrecht needed a strong ally and for that purpose he chose the Grand Duchy of Lithuania, taking into account the interests of the Duchy in Livonia. The Lithuanian politicians were favourably disposed to the collaboration with the Prussian Duke, at the same time endevouring to direct his activity so as to derive more profit for Lithuania. Albrecht had served Lithuania as a locomotive force in a long and difficult preparatory work already since 1529. Sigismundus Augustus, Chancellor Nicolaus Radvila the Black and a number of other nobles supported the Duke’s aspirations, however every party envisaged the final result differently, and that was fraught with a split.Thus in the first period of the struggle for the domination in Livonia, i.e., in 1552-1557 - from the birth of the idea up to the signing of the Pasvalys treaties - there were two interacting trends, represented by Albrecht and Radvila; their plans were influenced by the political processes, taking place in the Holy Roman Empire, Poland and in the countries of the Baltic region, and also by the struggle of the forces, supporting Reformation or Catholicism. In 1556-1557 the conflict between the Grand Duchy Lithuania and the Livonian Order became overt, and the question of Livonian statehood was being solved not in the direct confrontation between the Duchy and the Order with the military balance being definitely in favour of Lithuania, but in the contest of the principal political trends, represented by the adherents of Reformation, in collaboration with the Hohenzollerns seeking to annex Livonia and increase the influence of the Protestants in the states of Sigismundus Augustus, and by the Catholics, enjoying the support of the Habsburgs as the defenders of their interests. During the negotiations at Pasvalys there was a shift of priorities in the policy of the Grand Duchy of Lithuania regarding Livonia. Previously attempts had been made to weaken the Order with the aim of the subsequent attachment of its lands to the Archdiocese of Riga - the Duchy’s ally and ward, which was to become a secular Livonian state; afterwards Lithuania began to rely on the Order. The domination of the Hohenzollern dynasty along a wide strip of the coast, separating the Grand Duchy of Lithuania and Poland from the Baltic Sea, was not in the interests of these states. Faced with the threat of a war with the state of Ivan the IV, Lithuania decided not to worsen relations with the Holy Roman Empire, ruled by the Habsburgs, and gave up the plans of realizing the Livonian project, suggested by Albrecht.The shift of priorities might also have been influenced by very weak positions of the Archbishop, suddenly defeated utterly by the Order. For the King and the Radvilas it was more important to have the Order - the mightiest power in Livonia - as an ally, whose support might be indispensable in the conflict with the principal rival of the Duchy - Moscow. In the first stage of its policy in regard to Livonia, the Grand Duchy of Lithuania closely collaborated with the rulers of the Hohenzollern dynasty, in particular with the Prussian duke Albrecht. Ostensibly passing the initiative in these matters to Albrecht and conferring on him wide powers, Lithuania was guided only by her own interests. Extending her influence in Livonia, the Duchy managed to prevent the formation of a united state of Prussia and Livonia under the rule of the Hohenzollerns by directing the energy of Albrecht von Brandenburg in the direction, desirable for the Duchy.