The region is called Podlasie, Podlasko or Podlasze in Polish, Palenkė in Lithuanian, Padliašša (Падляшша) in Belarusian, Podljas’e (Подлясье) in Russian, פּאָדליאַשע Podlyashe in Yiddish, and Podlachia in Latin.

[3] However, this hypothesis conflicts with historical phonology; it fails to explain the vocalism and especially the -ch-/-š- in Slavic languages and the -nk- in Lithuanian.

The origin of this name is apparently in East Slavic, probably Old Ruthenian ljax, as the descendants of the Proto-Slavic word *lęxъ 'Pole' are most widespread there; there is no trace of nasalisation as would be expected in a native Polish word, but instead the typically East Slavic reflex -ja-, betraying the non-Lechitic origin.

In the 9th and 10th centuries, the area was inhabited by East Slavic tribes, mostly by Drevlians, with settlements of Dregoviches to the north beyond the Narew River and likely Dulebes to the south,[3] although a Masovian-like population had also been present.

[5] In the 14th century the area was annexed by the Grand Duchy of Lithuania, although it later briefly fell under Mazovian Piast rule.

In the 18th and 19th century the private town of Białystok became the main center of the region, thanks to the patronage of the Branicki family and the development of the textile industry.

Following the 1795 Third Partition of Poland which brought an end to Poland-Lithuania, the former Podlachia Voivodeship was divided between the Kingdom of Prussia and the Habsburg monarchy (Austrian Empire from 1804), with the Bug forming the border between them.

In theory this kingdom was created as an autonomous entity but in practice its separate laws and freedoms were simply ignored by the Emperors and control was steadily centralised, particularly following the November and January Uprisings (1830–31, 1863–64).

As a result of the uprising, in 1867 Congress Poland was formally absorbed into Russia as the Vistula Land (Privislinsky Krai), although the Kingdom still nominally existed.

According to the Russian Imperial Census of 1897, the most spoken languages in the Siedlce Governorate were Polish (66.13%), Yiddish (15.56%) and Ukrainian (13.95%).

During World War I the area was occupied by the German Empire, with most of the Vistula Land falling under the Government General of Warsaw (later the Central Powers puppet Kingdom of Poland) while the areas further east, including Białystok and the Suwałki Governorate, fell under Ober Ost.

Although the border agreed upon in the Pact would have given all of Podlachia to the Soviet Union, the final border agreed upon in the German–Soviet Boundary and Friendship Treaty signed after the invasion gave the southern part to the Nazi General Government, while the northern part of Podlachia was annexed by the Soviet Union as the Belastok Region of the Byelorussian SSR.

Under German occupation, the population was subjected to mass arrests, executions and deportations to forced labour, concentration camps and Nazi ghettos, whereas under Soviet occupation the population was subjected to mass arrests, executions, deportations to forced labour in Siberia, Central Asia and the Far North.

[20] Orthodox autochthonous inhabitants are known as khakhly (without any negative connotations, though today in Ukraine it is known as an ethnic slur for Ukrainians).

In 1875, Russians forbade this rite in the southern portion as well, and all Greek-Catholic inhabitants were forced to accept the Eastern Orthodox faith.

However, the resistance of the local people was surprisingly strong and Ruthenian speakers from this area rejected the separation from the Pope.

In reaction to these measures, the Ruthenians of southern Podlachia began to identify themselves with the national movement of the Roman Catholic Poles.

To preserve the full communion with the Pope, they changed their rite from Eastern to Latin before the compulsory conversion of Greek Catholics into Orthodox.

In 1912, Russian authorities issued a tolerance edict that made it possible to change confession from Orthodox to Roman Catholic (but not to Greek-Catholic, which had been completely deleted).

In 1992, the Union of Tatars of the Republic of Poland (Związek Tatarów Rzeczypospolitej Polskiej) with autonomous branches in Białystok and Gdańsk began operating.