LVIV, Ukraine — Olesia Kuzo of Sacramento, California, prepares the traditional Ukrainian Christmas play called vertep. Her three daughters and children of relatives and friends will take part. Kuzo adapted and remade three different scenarios and conducted the rehearsals.

The Ukrainian Christmas play is rather special — there is no baby Jesus or Mary or Joseph, but there are angels and shepherds, King Herod and prophets, along with the characters of death and the devil.

“We decided to leave out the death character as these are small children,” said Kuzo.

The vertep will be played in the Ukrainian Catholic parishes in Sacramento and San Francisco on December 25 and January 7. These are two dates Ukrainians celebrate Christmas — according to the Gregorian and Julian calendars.

The Gregorian calendar was introduced by Pope Gregory XIII in 1582, but it was not recognized by the Orthodox world and by some Eastern churches, which continue to follow the Julian calendar. In the U.S. and Canada, some Eastern Catholic parishes celebrate feasts according to one calendar or the other, and some parishes even have two separate calendar communities.

After living in the United States for 10 years, the Kuzo family now celebrates with the majority of Americans. In the past, it was hard to explain why the Ukrainians did not celebrate with all the Americans if they were celebrating the same Christmas.

Oleh Kuzo, the children’s father, explained they would be on Christmas vacation, “but we didn’t celebrate, then the holidays are over, I was back to work, girls to school and then suddenly in the middle of the week — our Christmas. So gradually, we decided to celebrate on December 25 and to drive to a San Francisco parish for Christmas liturgy and celebration. Logistics sometimes wins.”

He said the family also celebrated Ukrainian Christmas, traditionally on January 7, with relatives.

Father Vasyl Rudeyko, a liturgy scholar at Ukrainian Catholic University, said that, in Ukraine, the economic reasons will also influence how and when families celebrate Christmas.

“We will have closer cooperation with the West, and those who work with the Western partners will face the issue,” he said.

He said he believes following the Julian calendar is harmful to the very understanding of the tradition.

“Faithful come to understanding that tradition should be illogical. However, every time the church created something new — architecture, liturgical chant, and iconography — it was always logical and understandable for everybody,” he told Catholic News Service.

In Ukraine, the issue of the Julian calendar became more acute after Russia invaded their country in 2014. Many faithful are questioning why Ukraine is celebrating Christmas like the Russian Orthodox Church. In the media, there are appeals to religious leaders to move the date of Christmas and “celebrate with the whole world.” Some, however, warn that this issue should be approached cautiously.

Earlier this year, some members of the Ukrainian parliament introduced a bill to make December 25 the official Christmas holiday, but one legislator told CNS the bill probably will not be considered this year.

Transitions from the Julian to Gregorian calendars have not always been smooth. In Chicago, the Ukrainian Catholic community survived the calendar revolution in the 1960s by splitting into two parishes.

“Now the calendar is not an issue. We visit each other during holidays. Moreover, even if we celebrate Christmas on different dates, we preserve the unity,” said a woman identified only as Khrystyna, who lives in Chicago and follows the Julian calendar.

Father Taras Lonchyna, pastor of St. Josaphat Ukrainian Catholic Parish in Trenton, New Jersey, said some Ukrainians in the United States “follow the Julian calendar, because this unites them with their families in Ukraine.”

The calendar is a matter of consensus, he added, noting that his parish celebrates “according to Ukrainian traditions, with the special Holy Supper on Christmas Eve, carols singing and liturgical services.”