Because the spring equinox was tied to the date of Easter, the Roman Catholic Church considered the seasonal drift in the date of Easter undesirable. The Church of Alexandria celebrated Easter on the Sunday after the 14th day of the moon (computed using the Metonic cycle) that falls on or after the vernal equinox, which they placed on 21 March. However, the Church of Rome still regarded 25 March as the equinox (until 342) and used a different cycle to compute the day of the moon. In the Alexandrian system, since the 14th day of the Easter moon could fall at earliest on 21 March its first day could fall no earlier than 8 March and no later than 5 April. This meant that Easter varied between 22 March and 25 April. In Rome, Easter was not allowed to fall later than 21 April, that being the day of the Parilia or birthday of Rome and a pagan festival.The first day of the Easter moon could fall no earlier than 5 March and no later than 2 April.
Where did the Church of Alexandria place the vernal equinox?
21 March

The Umayyad caliphate was marked both by territorial expansion and by the administrative and cultural problems that such expansion created. Despite some notable exceptions, the Umayyads tended to favor the rights of the old Arab families, and in particular their own, over those of newly converted Muslims (mawali). Therefore, they held to a less universalist conception of Islam than did many of their rivals. As G.R. Hawting has written, "Islam was in fact regarded as the property of the conquering aristocracy."
What is another name for people who recently converted to Islam?
mawali

The Oeselians or Osilians (Estonian saarlased; singular: saarlane) were a historical subdivision of Estonians inhabiting Saaremaa (Danish: Øsel; German: Ösel; Swedish: Ösel), an Estonian island in the Baltic Sea. They were first mentioned as early as the second century BC in Ptolemy's Geography III. The Oeselians were known in the Old Norse Icelandic Sagas and in Heimskringla as Víkingr frá Esthland (Estonian Vikings). Their sailing vessels were called pirate ships by Henry of Latvia in his Latin chronicles written at the beginning of the 13th century.
Who described the sailboats of the Estonians as pirate ships?
Henry of Latvia