Irish history is complex. This shouldn’t need to be said, but it’s increasingly necessary to say it. As the drumbeat for a Border Poll grows louder and the blight of tricolours spreads wider, the power of simple certainties is growing stronger. We should step back. The Oasis concerts in Croke Park in August were a triumph. For those of us lucky enough to be there, we shared an emotional blending of song, band, and surroundings.  Beyond music, it was a complicated homecoming. An emotional return to a time and a place etched deeply in the collective memory of band and…