What does claudius accomplish in his opening speech?

He wants to take care of matters at hand, explains his hasty marriage, and 
plans to send a letter to old Norway to warn him of fortuitous threat and to put an end to it. 

The gregorian chant was a major cultural milestone in the middle ages. it was one of the first codified forms of music meant to be played as written, where previously it was difficult to mass-produce and disseminate any music. what's more, these chants were also some of the first examples of musical notation: the notes and bars of today's music sheets are a reflection of centuries of evolution beginning with these chants. it became official throughout the entirety of the catholic church, meaning that nearly all of europe followed this musical notation and styling.