Time Span of the Novel
The biblical story
The biblical events of the novel start in the morning of the fourteenth day of the spring month of Nisan to end late in the night of the Jewish feast of Passover. Nisan is, according to the civil calendar, the seventh month of the Jewish lunar calendar. Originally, according to the ecclesiastical calendar, it was the first month. The fifteenth day of Nisan (beginning at the sunset of the fourteenth) is the start of the feast of Pesach or Passover, (Hebrew: פסח - coming from Pasach which means passing over). It's the day of the full moon, because the jewish months start on the day following the new lunar crescent. Passover or Pesach is also known as the spring feast, the freedom feast, or the feast of matza, commemorating the exodus of the Jews from Egypt.
Traditionally it is assumed that the fourteenth day of the spring month of Nisan on which Christ was crucified, was on a Friday. Because we know from the Bible that Jesus had to be burried soon after he died, before dark and the start of the sabbat, which is always on a Saturday.
The actions in Moscow
The actions in Moscow in the novel take places from Wednesday night until the night between Saturday and Sunday. That night the master finds peace, and Pilate finds mercy. This timeline shows strong similarities with the one of the Christian Easter week, which culminates at the night from Saturday to Sunday with the Resurrection of Christ. So the chronology of the events in Moscow are in line with the second part of the christian Holy Week, from the eve of Maundy Thursday to the night of Easter.
At the beginning of the novel, however, Bulgakov writes that the discussion between Berlioz and Bezdomny at Patriarch's Ponds took place on «a dreadful May evening» (Richard Pevear and Larissa Volokhonsky) or «a terrible day in May» (Michael Glenny). Many Western critics see this as a proof that the Moscow scenes from The Master and Margarita can never play in the Easter week, because the Christian Easter always falls on a Sunday between March 22 and April 25, and never in the month of May.
The Russian Christians profess, after all, the Russian orthodox doctrine, in which Easter is always celebrated on a Sunday between April 3 and May 9. So, for Orthodox Christians, Easter can indeed be celebrated in May. Between 1928 and 1940, the period in which Bulgakov wrote The Master and Margarita, it occured even three times: in 1929 , 1932 and 1937.
The Walpurgis Night
According to the French Bulgakov expert Marianne Gourg, Woland's ball coincides with the Walpurgis night and its witches' sabbath, which is celebrated each year on the night of April 30 to May 1 in large parts of northern and central Europe.
This statement is less likely. Indeed, if the scene at Patriarch's Ponds took place on «a dreadful May evening», as Bulgakov wrote, the Walpurgis Night was already past.
For trivia: in 1932, when Bulgakov was working on the third version of The Master and Margarita, the Orthodox Easter and the Walpurgis Night were celebrated on the same day. But this can not be a reason to situate Woland's ball on Walpurgis Night either because, in such case, Berlioz and Bezdomny would have had their conversation at the Patriarch's Ponds on «a dreadful April evening», quod non.
It is not always easy to link dates from the Soviet history to our current calendar system. After all, the Soviet regime changed its calendar system more than once.
In 1923, a radical change in the calendar took place. The Soviet Union abolished both the official Gregorian calendar - installed by Vladimir Ilyich Lenin (1870-1924) - and the Julian calendar - which was still used by the Russian Orthodox Church. A new calendar was introduced, in which the weeks were changed and all religious feasts and holy days were replaced by five national public holidays associated with the Revolution.
This Eternal Calendar went into effect on October 6, 1923, giving five days to the weeks and six weeks to the months, so that there were 12 months of 30 days, plus five holidays with national names instead of weekday names. The main purpose of the Eternal Calendar was to increase productivity. Rest-days became staggered without realizing at the time that such an arrangement would cause real hardship to family life.
You can read much more on the calendar issues in the Soviet Union in the Context section of this website.