It’s not yet noon on a grey Sunday early in December. The temperature hovers around freezing. I decide to swing over to Rockefeller Center on the way home from Mass. I want to take in the festive scene. Even at this early hour, tourists are massing on the street corners up and down Fifth Avenue. Police barricades are set up to keep the throngs from spilling onto the roads and bringing the already congested traffic to a standstill. All of this will get more intense in the afternoon. By sundown the 15ft-wide sidewalks along the avenues will be impossibly crowded. That’s because people love to come into New York during what we wrongly call the Christmas season: the weeks of preparation for the coming of the promised Messiah, the season of Advent. The chestnuts may not be – as Nat King Cole crooned – “roasting on an open fire”, but you can buy them from street vendors whose propane flames do the job. Shops trim their windows with evergreens and all manner of shimmering foil. Shopping bags are filled. Ribbons are everywhere.