Walk with me just a tiny bit down Memory Lane. I first went to Oslo in 2010. Some locals told me that, no matter what the official statistics were, the Muslim population of the city could be as high as 25 percent. Walk 15 or 20 minutes away from the center of town, they said, and you’ll think you’re in the Middle East, or Pakistan.

I did. And they were right.

In an “Oslo Journal” that year, I wrote the following:

Norway, like other countries on this continent, has a growing Muslim population. It is something like 8 percent in the country at large. In Oslo, it may be more like 25 percent. Norwegian Muslims lead largely separate lives; assimilation has been a problem, here as all over. In December 2008 and January 2009, Muslims rioted through the streets of Oslo. That was when Israel was carrying out its counterterror operation in Gaza. The rioting, which featured Molotov cocktails and rocks, was harrowing. Innocents were cowed and terrified. Shouts of “Kill the Jews!” rang out.

When I published this journal, I received an e-mail from an expat Norwegian. He said, “Are you telling me that one out of every four residents in my native capital is a Muslim? That is crazy.” I wondered: “Is it?”

I thought of this four-year-old exchange when reading this headline last week: “Mohammed is most popular name in Oslo.” I can well believe it: because I have taken those walks, beyond the center of town.

In the article, a Norwegian statistician is quoted as saying, “It is very exciting.” He means Mohammed as the most popular name. It could be that these kids will integrate, will blend, will become Norwegians rather like the Pers and Jans and Bjørns. Maybe they’ll listen to Grieg, eat herring, and enjoy the oil wealth. (Muslims in Norway can live like Gulf Arabs!) But if integration and assimilation do not occur — that statistician may find his country more “exciting” than he wishes.