Alfonsas Konstantinas Petrulis (; 4 August 1873 – 28 June 1928) was a Lithuanian Roman Catholic priest and one of the twenty signatories of the Act of Independence of Lithuania.

Petrulis attended priest seminaries in Kaunas and Vilnius. Due to poor health, he did not complete his studies at the Saint Petersburg Roman Catholic Theological Academy. He was ordained in 1899 and served as parish priest in nine different parishes of the Diocese of Vilnius and later the Diocese of Kaišiadorys. His longest tenure was 16 years spent in Pivašiūnai (1911–1927).

At the time, there were increasing tensions between Lithuanians and Poles and such frequent reassignments were likely caused by Petrulis pro-Lithuanian activities – he sought to deliver masses and sermons in Lithuanian, organize church choirs, established local chapters of Lithuanian societies, etc. This brought him into conflict with Polish activists. In 1909, Petrulis became a member of the five-member commission established by the diocese administrator Kazimierz Mikołaj Michalkiewicz to mediate local disputes between Lithuanians and Poles. In 1911, Petrulis became one of the co-founder of the biweekly Lithuanian newspaper Aušra which promoted the Lithuanian language, particularly in churches, among Lithuanians in Vilnius Region. Petrulis became one of the co-founders and board members of the Lithuanian Education Society Rytas in 1913.

In September 1917, he was elected by the Vilnius Conference to the 20-member Council of Lithuania which adopted the Act of Independence on 16 February 1918. He traveled twice to Switzerland to attend the Lithuanian conferences in Bern and Laussane. Petrulis became involved with the Party of National Progress and campaigned in the April 1920 election to the Constituent Assembly of Lithuania. However, the party won no seats and Petrulis retired from political life. He returned to pastoral duties until his death in 1928.

Early life and education Alfonsas Konstantinas Petrulis was born on 4 August 1873 in near Vabalninkas which was then part of the Russian Empire. His parents were Lithuanian farmers who owned of land. Petrulis had four siblings – two sisters and two brothers. Alfonsas supported and financed education of his younger brother Vytautas Petrulis. Vytautas became the Minister of Finance (1922–1925) and Prime Minister of Lithuania (1925).

It appears the Petrulis did not attend a primary school and was educated at home. In August 1884, he enrolled directly at the eight-year Šiauliai Gymnasium. He was left the gymnasium after completing five classes in September 1889. He wanted to attend Kaunas Priest Seminary but was too young and had to wait until October 1891. One of his classmates was Kazimieras Steponas Šaulys, another signatory of the Act of Independence.

Petrulis studied at the seminary until 1895. On 20 December 1892, he received the four minor orders from bishop Mečislovas Leonardas Paliulionis but was not ordained priest. This is explained that he was either too young or still questioning his religious calling. In 1895, he enrolled at the Imperial Veterinary Institute in Lviv (then part of Austria-Hungary). During that time, he lived in Sokilnyky and assisted the local priests. In 1897, he dropped out from the veterinary institute and enrolled at Vilnius Priest Seminary for a year to finish his priest education.

Petrulis was then sent to study at the Saint Petersburg Roman Catholic Theological Academy. However, due to poor health, he returned to Vilnius in early 1899. After he recovered, he was ordained priest on 4 April 1899 by bishop Stefan Aleksander Zwierowicz. Three weeks later, Petrulis was appointed as vicar to the Church of St. Peter and St. Paul in Vilnius.

Priesthood Petrulis was moved to seven different parishes in ten years between 1899 and 1909. At the time, there were increasing tensions between Lithuanians and Poles in the Diocese of Vilnius and such frequent reassignments were likely caused by Petrulis pro-Lithuanian activities – he sought to deliver masses and sermons in Lithuanian, organize church choirs, established local chapters of Lithuanian societies, etc.

Bogdanova and Joniškis On 7 December 1899, Petrulis was assigned to the filial church in in the parish of Halshany (present-day Belarus). On 27 January 1901, Petrulis was reassigned as parson to the parish in Joniškis. There, he resisted the pressure from a local noble to deliver sermons only in Polish. After Petrulis' departure, the noble organized a group of about ten farm workers which harassed Lithuanian speakers and interrupted Lithuanian masses. The conflict culminated in a trial of the noble and workers for disturbing public peace. Petrulis was one of 88 witnesses in the case. Eight people received prison sentences, but were pardoned on the occasion of the Romanov Tercentenary in 1913.

Maišiagala On 12 August 1903, Petrulis was assigned to the parish in Maišiagala. He instituted weekly Catechism lessons and monthly sermons in Lithuanian. He also organized a Lithuanian primary school. Even such limited Lithuanian activities were attacked in the Polish press, including Goniec Wieczorny and Dziennik Wileński. Petrulis was accused of forcing locals to learn Lithuanian and using Lithuanian for various prayers. The accusations were debunked in Kurier Litewski.

In early 1906, Petrulis was questioned by the Tsarist police on suspicion that he agitated adherents of the Eastern Orthodox Church in Dūkštos to convert to Roman Catholicism. Petrulis explained that this was allowed under the Imperial decree adopted in April 1905.

In March 1904, Petrulis started repairs of the church in Maišiagala – replace wood shakes roof with roof tiles over the church and sheet metal over the church tower, construct a small building in the churchyard to house church's implements and host wakes, and construct a clergy house. Petrulis agreed to finance the clergy house personally and that left him in debt. Eventually, Petrulis was able to repay the full debt of 1,050 rubles in 1912.

Nalibaki and Marcinkonys

On 25 September 1907, Petrulis was assigned to the parish Nalibaki which had about 7,000 Catholics. The former pastor of Nalibaki instigated local residents to protest and complain about Petrulis demanding his return. Thus, they complained to the bishop at least three times and to the authorities of Vilna Governorate. His superiors investigated the complaints and found them untrue, but Petrulis was still reassigned to the smaller filial church in Marcinkonys on 31 October 1907.

Marcikonys were inhabited mainly by Lithuanians, thus Petrulis could work on Lithuanian causes without a conflict with the Poles. He completed church's repairs and purchased a new organ constructed by . He hired an experienced organist who organized a church choir. He also invited members of the Rūta Society to perform in Marcinkonys – they staged two Lithuanian plays and sung songs, including "Tautiška giesmė", on 16 July 1909. When he could not get the local Russian primary school to add lessons in Lithuanian, Petrulis established a secret Lithuanian school. Tsarist police discovered it and Petrulis was put on trial, but he was acquitted in November 1910. He purchased various Lithuanian periodicals and books, and encouraged villagers to read them.

In December 1909, Petrulis consecrated the new church in Dubičiai. In September 1920, Petrulis supported a local group of Lithuanian Riflemen in Pivašiūnai by supplying them with 10 rifles and 500 bullets.

Pivašiūnai

On 22 April 1911, Petrulis was assigned to Pivašiūnai where he spent 16 years. The parish had about 5,000 Catholics of which about 3,000 were Lithuanians. Petrulis launched Lithuanian sermons, lessons in Catechism, organized a Lithuanian choir. This angered local Polish nobles who complained to his ecclesiastical superiors. Diocese administrator Kazimierz Mikołaj Michalkiewicz sent Vladas Mironas and to investigate the complaints, but they found them untrue. Accusations against Petrulis were published in Kurier Wileński claiming that he incited violence against Poles, pushed and hit a Polish nobleman who came to discuss an event, refused to hear confessions in Polish, etc. Petrulis sued the newspaper for defamation and was represented by attorney Petras Leonas. Petrulis won in district court, but lost on appeal. Further complaints were made to Tsarist authorities who searched the clergy house in early 1912 hoping to find evidence of an illegal school. Further complaints about Petrulis and his insistence on using the Lithuanian language were made in 1915 and 1918.

Petrulis organized and became chairman of the local chapters of the Lithuanian Education Society Rytas in August 1913 and the Lithuanian Catholic Temperance Society in November 1913. Petrulis also took over town's struggling consumer cooperative and improved its shop. During World War I, Petrulis organized a local society to provide aid to war refugees and organize primary schools. In 1917, nine parish's villages had Lithuanian schools and three villages had Polish schools. The church bells were taken by soldiers to Russia, but Petrulis was able to purchase a new organ and other church implements.

During the Polish–Lithuanian War, Petrulis was briefly arrested twice by the Polish troops in September 1919.

Last years

On 2 May 1924, Petrulis became dean of Stakliškės (he continued to be the parish priest in Pivašiūnai). When the Diocese of Kaišiadorys was formed in 1926, he became dean in Alytus. His health began to deteriorate. He spent about two months in early 1927 seeking treatments in Germany and France. Upon return, he was reassigned from Pivašiūnai to the parish of on 30 May 1927. In August 1927, in a letter to bishop Juozapas Kukta, Petrulis reported that he suffered from pleurisy and kidney ailments, was treated by doctor Vladas Kairiūkštis, and was cared for by his brother Vytautas Petrulis.

Petrulis was reassigned to the parish in Musninkai on 7 March 1928. He died there from a heart attack on 28 June 1928. He was buried in the churchyard two days later. Funeral speeches were given by his associate Vladas Mironas, brother Vytautas, and government representative . His grave monument, which includes a copy of Christus by Bertel Thorvaldsen, was added to the Registry of Cultural Property in 1996.

Activism Language of prayers Lithuanian prayers were full of loan words and barbarisms. Therefore, in 1909, priests Adomas Jakštas, Juozas Laukaitis, and Petrulis formed a committee to review and revise the Lord's Prayer and other Christian prayers. Petrulis was not an expert in this field and mainly deferred to the other two members. The priests were assisted by linguists, but in a few instances they did not dare change the almost 400-year tradition and fully implement linguists' suggestions. However, they much improved the language and the revised prayers were officially adopted at the end of World War I.

In April 1909, Petrulis attended a meeting organized by the Archdiocese of Warsaw to review and revise Catholic rites that were used in the diocese since 1634. However, in private correspondence, Petrulis considered the meeting a waste of time.

Polish–Lithuanian relations In June 1906, Petrulis published an article in Vilniaus žinios arguing that Lithuanians needed to petition the Holy See directly so it could be informed about the ongoing Polonization and discrimination against the Lithuanians in Catholic churches. In late 1907, Jonas Basanavičius organized such delegation and invited Petrulis. However, Petrulis complained of financial difficulties and inability to leave the parish for a prolonged period of time. Additionally, the Diocese of Vilnius forbade its priests from traveling to Rome. Therefore, the plans fell through.