structural:expansion, linguistic:paraphrasing
Works

Mickiewicz's childhood environment exerted a major influence on his literary work. His early years were shaped by immersion in folklore and by vivid memories, which he later reworked in his poems, of the ruins of Navahrudak Castle and of the triumphant entry and disastrous retreat of Polish and Napoleonic troops during Napoleon's 1812 invasion of Russia, when Mickiewicz was just a teenager. The year 1812 also marked his father's death. Later, the poet's personality and subsequent works were greatly influenced by his four years of living and studying in Vilnius.

His first poems, such as the 1818 Zima miejska (City Winter) and the 1819 Kartofla (Potato), were classical in style, influenced by Voltaire. His Ballads and Romances and poetry anthologies published in 1822 (including the opening poem Romantyczność, Romanticism) and 1823 mark the start of romanticism in Poland. Mickiewicz's influence popularized the use of folklore, folk literary forms, and historism in Polish romantic literature. His exile to Moscow exposed him to a cosmopolitan environment, more international than provincial Vilnius and Kaunas in Lithuania. This period saw a further evolution in his writing style, with Sonety (Sonnets, 1826) and Konrad Wallenrod (1828), both published in Russia. The Sonety, mainly comprising his Crimean Sonnets, highlight the poet's ability and desire to write, and his longing for his homeland.

One of his major works, Dziady (Forefathers' Eve), comprises several parts written over an extended period of time. It began with publication of parts II and IV in 1823. Miłosz remarks that it was "Mickiewicz's major theatrical achievement", a work which Mickiewicz saw as ongoing and to be continued in further parts. Its title refers to the pagan ancestor commemoration that had been practiced by Slavic and Baltic peoples on All Souls' Day. The year 1832 saw the publication of part III: much superior to the earlier parts, a "laboratory of innovative genres, styles and forms". Part III was largely written over a few days; the "Great Improvisation" section, a "masterpiece of Polish poetry", is said to have been created during a single inspired night. A long descriptive poem, Ustęp (Digression), accompanying part III and written sometime before it, sums up Mickiewicz's experiences in, and views on, Russia, portrays it as a huge prison, pities the oppressed Russian people, and wonders about their future. Miłosz describes it as a "summation of Polish attitudes towards Russia in the nineteenth century" and notes that it inspired responses from Pushkin (The Bronze Horseman) and Joseph Conrad (Under Western Eyes). The drama was first staged by Stanisław Wyspiański in 1901, becoming, in Miłosz's words, "a kind of national sacred play, occasionally forbidden by censorship because of its emotional impact upon the audience." The Polish government's 1968 closing down of a production of the play sparked the 1968 Polish political crisis.

Mickiewicz's Konrad Wallenrod (1828), a narrative poem describing battles of the Christian order of Teutonic Knights against the pagans of Lithuania, is a thinly veiled allusion to the long feud between Russia and Poland. The plot involves the use of subterfuge against a stronger enemy, and the poem analyzes moral dilemmas faced by the Polish insurgents who would soon launch the November 1830 Uprising. Controversial to an older generation of readers, Konrad Wallenrod was seen by the young as a call to arms and was praised as such by an Uprising leader, poet Ludwik Nabielak. Miłosz describes Konrad Wallenrod (named for its protagonist) as "the most committed politically of all Mickiewczi's poems." The point of the poem, though obvious to many, escaped the Russian censors, and the poem was allowed to be published, complete with its telling motto drawn from Machiavelli: "Dovete adunque sapere come sono due generazioni di combattere – bisogna essere volpe e leone." ("Ye shall know that there are two ways of fighting – you must be a fox and a lion.") On a purely literary level, the poem was notable for incorporating traditional folk elements alongside stylistic innovations.

Similarly noteworthy is Mickiewicz's earlier and longer 1823 poem, Grażyna, depicting the exploits of a Lithuanian chieftainess against the Teutonic Knights. Miłosz writes that Grażyna "combines a metallic beat of lines and syntactical rigor with a plot and motifs dear to the Romantics." It is said by Christien Ostrowski to have inspired Emilia Plater, a military heroine of the November 1830 Uprising. A similar message informs Mickiewicz's " Oda do młodości " (" Ode to Youth ").

Mickiewicz's Crimean Sonnets (1825–26) and poems that he would later write in Rome and Lausanne, Miłosz notes, have been "justly ranked among the highest achievements in Polish." His 1830 travels in Italy likely inspired him to consider religious matters, and produced some of his best religiously themed works, such as Arcymistrz (The Grand Master) and Do Marceliny Łempickiej (To Marcelina Łempicka). He was an authority to the young insurgents of 1830–31, who expected him to participate in the fighting (the poet Maurycy Gosławski wrote a dedicated poem urging him to do so). Yet it is likely that Mickiewicz was no longer as idealistic and supportive of military action as he had been a few years earlier, and his new works such as Do Matki Polki (To a Polish Mother, 1830), while still patriotic, also began to reflect on the tragedy of resistance. His meetings with refugees and escaping insurgents around 1831 resulted in works such as Reduta Ordona (Ordon's Redoubt), Nocleg (Night Bivouac) and Śmierć pułkownika (Death of the Colonel). Wyka notes the irony that some of the most important literary works about the 1830 Uprising were written by Mickiewicz, who never took part in a battle or even saw a battlefield.

His Księgi narodu polskiego i pielgrzymstwa polskiego (Books of the Polish Nation and the Polish Pilgrimage, 1832) opens with a historical-philosophical discussion of the history of humankind in which Mickiewicz argues that history is the history of now-unrealized freedom that awaits many oppressed nations in the future. It is followed by a longer "moral catechism " aimed at Polish émigrés. The book sets out a messianist metaphor of Poland as the " Christ of nations ". Described by Wyka as a propaganda piece, it was relatively simple, using biblical metaphors and the like to reach less-discriminating readers. It became popular not only among Poles but, in translations, among some other peoples, primarily those which lacked their own sovereign states. The Books were influential in framing Mickiewicz's image among many not as that of a poet and author but as that of ideologue of freedom.

Pan Tadeusz (Sir Thaddeus, published 1834), another of his masterpieces, is an epic poem that draws a picture of the Grand Duchy of Lithuania on the eve of Napoleon's 1812 invasion of Russia. It is written entirely in thirteen-syllable couplets. Originally intended as an apolitical idyll, it became, as Miłosz writes, "something unique in world literature, and the problem of how to classify it has remained the crux of a constant quarrel among scholars"; it "has been called 'the last epos' in world literature". Pan Tadeusz was not highly regarded by contemporaries, nor by Mickiewicz himself, but in time it won acclaim as "the highest achievement in all Polish literature."

The occasional poems that Mickiewicz wrote in his final decades have been described as "exquisite, gnomic, extremely short and concise". His Lausanne Lyrics, (1839–40) are, writes Miłosz, "untranslatable masterpieces of metaphysical meditation. In Polish literature, they are examples of that pure poetry that verges on silence."

In the 1830s (as early as 1830; as late as 1837) he worked on a futurist or science-fiction work, A History of the Future. (Historia przyszłości, or L’histoire d’avenir) It predicted inventions similar to radio and television, and interplanetary communication using balloons. Written partially in French, it was never completed and was partly destroyed by the author, but parts of its seven versions survive. Other French-language works by Mickiewicz include the dramas Konfederaci barscy (The Bar Confederates) and Jacques Jasiński, ous les deux Polognes (Jacques Jasiński, or the Two Polands). These would not achieve much recognition, and would not be published till 1866.