IT IS the Texas border, and hoards of undocumented migrants are flooding in, refusing to learn the language or culture of their new home. They bring only crime and dissent; but these are not the “bad hombres” of Donald Trump’s election rhetoric. They are the Anglo-Americans of the 1820s who settled in northern Texas when it was still a part of Mexico. To cut a long story short, there was a little ding-dong at the Alamo, and it did not turn out well for Mexico.

The scholar featured in The Inven­tion of the USA (Radio 4, Mondays) who used the term “undocumented migrants” was undoubtedly having a dig; nothing can be said about the his­tory of the US at the moment which is not coloured by the Trump presid­ency. But Misha Glenny’s survey of the early years of the US is classier than that; and there is much to enjoy for its own sake without being invited to congratulate the smug historian on his “Told you so” T-shirt.

Take, for instance, the constant skirmishes that took place in the early 19th century along the US-Canadian border: they had names such as “the Lumberjack War”, and “the Pork and Beans War”. This is what inspires the historical imagination; this, and the sheer magnitude and dispropor­tionate casualness with which land masses were grabbed, purchased, or bestowed on the emerging nation.

No wonder the hubris was turned into the quasi-religious colonialist ideology of “manifest destiny”. It all made me yearn for another rich historical period: when Alistair Cooke was on the telly.

Music Matters (Radio 3, Saturday) did not inspire to the same extent, although perhaps it should be judged as part of the totality of Radio 3’s impressive Monteverdi 450 season. Festival promoters and programme makers like nothing better than an anniversary, and much has changed in our appreciation of Monteverdi since the last anniversary oppor­tunity.

Performers such as Sir John Eliot Gardiner have transformed our under­­standing of the music; and one of the most interesting segments in Sara Mohr-Pietsch’s documentary told how in the 1950s, before the Monteverdi revi­val, scores of his madrigals would be imported from abroad and sung on exclusive music courses by musicians such as the young and impressionable Sir John.

If your birthday boy is also a radical, even better; and Monteverdi certainly fulfils the criteria here, trans­forming emergent music theatre from mere “favola in musica”, performed in front of a few cognoscenti, into fully fledged, public opera.

Unlike the spare monody of Mon­te­­verdi’s operas, there are some musical styles that seem to lend themselves effortlessly to encultura­tion, however alien they might be. So the singing nun from Nepal, Ani Choying Drolma, who was the subject of Out­look (World Service, Monday of last week), should not have been sur­prised when a record producer from the United States offered her stardom in return for appearing on an album.

In our apparently ceaseless quest for the musical other, Drolma is a gift from whichever gods the West are comfortable to flirt with.