Today is the festival Navigius Isidis and Ash Wednesday.
The Navigium Isidis or Isidis Navigium (trans. the vessel of Isis) was an annual ancient Roman religious festival in honor of the goddess Isis,held on March 5.The festival outlived Christian persecution by Theodosius (391) and Arcadius' persecution against the Roman religion.
In the Roman Empire, it was still celebrated in Italy at least until the year 416. In Egypt, it was suppressed by Christian authorities in the 6th century.
Modern carnival resembles the festival of the Navigium Isidis, and some scholars argue that they share the same origin (via carrus navalis - meaning naval wagon, ie. float - later becoming car-nival).Many elements of Carnival were in turn appropriated in the Corpus Christi festival, most prominently in the Iberian Peninsula (Spain and Portugal).
The early Pagan origins of Ash Wednesday:
This ritual “imposition of the ashes” is purportedly in imitation of the repentant act of covering oneself in dust and ashes. The marking of believers on Ash Wednesday is done in combination of another extra-biblical routine called “Lent.” Despite Christ's command to his followers to abstain from the practice ofdisfiguring their faces during fasting, it has become a regular practice. He also told us to wash our faces during a fast.
The practice of putting ashes on one’s forehead has been known from ancient times. In the Nordic pagan religion, placing ashes above one’s brow was believed to ensure the protection of the Norse god, Odin. This practice spread to Europe during the Vikings conquests. This laying on of ashes was done on Wednesday, the day named for Odin, Odin’s Day. Interestingly enough, according to Wikipedia, one of Odin's names is Ygg. The same is Norse for the World Ash. This name Ygg, closely resembles the Vedic name Agni in pronunciation.
The Norse practice which has become known as Ash Wednesday was itself, drawn from the Vedic Indian religion. Ashes were believed to be the seed Agni , the Indian fire god. It is from this name that the Latins used for fire, ignis. It is from this root word that the English language got the words, ignite, igneous and ignition. Agni was said to have the authority to forgive sins. Ashes were also believed to be symbolic for the purifying blood of the Vedic god Shiva, which it is said had the power to cleanse sins.