Question: Who changed the date of the day of the dead?

Disambiguated questions and answers:
context: The holiday is sometimes called Día de "los" Muertos in Anglophone countries, a back-translation of its original Mexican name, "Día de Muertos". It is particularly celebrated in Mexico where the day is a public holiday. Prior to Spanish colonization in the 16th century, the celebration took place at the beginning of summer. Gradually, it was associated with October 31, November 1, and November 2 to coincide with the Western Christian triduum of Allhallowtide: All Saints' Eve, All Saints' Day, and All Souls' Day. Traditions connected with the holiday include building private altars called "ofrendas", honoring the deceased using calaveras, aztec marigolds, and the favorite foods and beverages of the departed, and visiting graves with these as gifts. Visitors also leave possessions of the deceased at the graves.
question: Which 16th century colonizers' presence, resulted in the date of the day of the dead changing?
short_answers: Spain
Spanish
wikipage: Day of the Dead
context: The holiday is sometimes called Día de "los" Muertos in Anglophone countries, a back-translation of its original Mexican name, "Día de Muertos". It is particularly celebrated in Mexico where the day is a public holiday. Prior to Spanish colonization in the 16th century, the celebration took place at the beginning of summer. Gradually, it was associated with October 31, November 1, and November 2 to coincide with the Western Christian triduum of Allhallowtide: All Saints' Eve, All Saints' Day, and All Souls' Day. Traditions connected with the holiday include building private altars called "ofrendas", honoring the deceased using calaveras, aztec marigolds, and the favorite foods and beverages of the departed, and visiting graves with these as gifts. Visitors also leave possessions of the deceased at the graves.
question: Which country did the date of the day of the dead gradually change?
short_answers: Mexico
wikipage: Day of the Dead

Long-form answers:
knowledge: content: The Day of the Dead (Spanish: Día de Muertos or Día de los Muertos)[1][2] is a Mexican holiday celebrated in Mexico and elsewhere associated with the Catholic celebrations of All Saints' Day and All Souls' Day, and is held on November 1 and 2. The multi-day holiday involves family and friends gathering to pray for and to remember friends and family members who have died. It is commonly portrayed as a day of celebration rather than mourning.[3] Mexican academics are divided on whether the festivity has indigenous pre-Hispanic roots or whether it is a 20th-century rebranded version of a Spanish tradition developed by the presidency of Lázaro Cárdenas to encourage Mexican nationalism through an "Aztec" identity.[4][5][6] The festivity has become a national symbol and as such is taught in the nation's school system, typically asserting a native origin.[7] In 2008, the tradition was inscribed in the Representative List of the Intangible Cultural Heritage of Humanity by UNESCO.[8
wikipage: Day of the Dead
long_answer: The Day of the Dead is a Mexican holiday that involves family and friends gathering to pray for and to remember friends and family members who have died. Prior to Spanish colonization of Mexico in the 16th century, the celebration took place at the beginning of summer, but it gradually became associated with the dates of October 31, November 1, and November 2.