Initially posted a similar and lengthy post in r/TrueFilm. The post was up for all of 30 seconds before someone suggested (painfully obviously, I must admit) that the question would do better on this sub.
For those who love film and have a knowledge of this time period and location... how accurate is Martin Scorsese’s ‘Gangs of New York’?
To add one small bit to the linked previous answers: the marching band you hear in the background at the start of the fight scenes is Otha Turner's Rising Fawn String Band, one of the only groups to carry on the tradition of African-American marching bands in the Hill Country of Mississippi. Great stuff, but a very, very odd choice for a battle circa 1870 between No-Nothings and Irish immigrants in New York .