Alexey ('Aleksey) (Russian: Алексе́й, [ɐlʲɪkˈsʲej]) (Bulgarian: Алексей, [aleksej]) is a Russian and Bulgarian male first name deriving from the Greek Alexios (Αλέξιος), meaning "Defender", and thus of the same origin as the Latin Alexius.
Alexey may also be romanized as "Alexei", "Aleksei", "Aleksey", "Alexej", "Aleksej", etc. It has been commonly westernized as Alexis.
Names of many persons of Ukrainian and Belarusian origin previously known as Alexey are now often romanized as Oleksiy (Олексiй) and Alyaxey (Аляксей), respectively.
The Russian Orthodox Church uses the Old Church Slavonic version, Alexiy (Алексiй, or Алексий in modern spelling), for its Saints and hierarchs (most notably, this is the form used for Patriarchs Alexius I and Alexius II).
The common hypocoristic is Alyosha (Алёша) or simply Lyosha (Лёша). These may be further transformed into Alyoshka, Alyoshenka, Lyoshka, Lyoha, Lyoshenka (Алёша, Алёшка, Алёшенька, Лёша, Лёшка, Лёха, Лёшенька), sometimes rendered as Alesha/Aleshenka in English. The form Alyosha may be used as a full first name in Bulgaria (Альоша) and Armenia.
Aleksei was a Russian archpriest who became known for converting to Judaism. He was born probably in Novgorod around 1425 and died in Moscow in 1488.
In the last quarter of the fifteenth century, when a schism arose in the Russian Orthodox Church and many new sects sprang up, Aleksei became a convert to Judaism. Some of the new sects had shown a decided tendency to revert to the old Mosaic law. This probably suggested to the influential Jew Skhariyah (Zechariah), of Kiev, the idea of spreading Judaism among the Russians of Pskov and Novgorod. Skhariyah belonged to the suite of the Gediminid Prince Michael Olelkovich, who came to Novgorod in 1471. The first convert in Novgorod was the priest Dionisy, who introduced to Skhariyah his colleague, the archpriest (protopop) Aleksei. The latter was the most zealous of the new converts, and did successful missionary work among all classes, especially among the clergy. The new community appreciated his labors so highly that the name of Abraham was conferred upon him, while his wife's name was changed to Sarah.