The conference I'm attending, LREC 2008, is being held in Marrakech, Morroco, "under the High Patronage of His Majesty King Mohammed VI". I don't know what this means in practical terms: does this patronage come with a subsidy, or is it simply a conventional phrase for events held at the government-run Palais des Congres, or what? I'll ask Khalid Choukry or one of the other conference organizers; but in fact, I'm more interested in the linguistic aspects of this "high patronage" than the practical ones.
I don't think I've ever seen the phrase "under the high patronage of X" used for a conference held in the U.S. or in the U.K. Certainly searches for phases like "under the High Patronage of George W. Bush" come up empty, and frankly such phrases sound faintly ridiculous to an American ear, or at least they do to mine. Even "under the High Patronage of Queen Elizabeth" is not now found on the web. So my first hypothesis is that this is a somewhat awkward translation of a formula used to refer to continental European royalty. But searching the web for other examples, I find X taking on not only royal values like "His Majesty the King of Spain" and "His Majesty King Abdullah II", but also republican values, like "the President of the Italian Republic" and "Mr. Nicolas Sarkozy, President of the French Republic".
The same search also shows that there's apparently a distinction of rank between "high patronage" and mere "patronage" — for example, the "2nd European eAccess Forum" (28 January 2008) was held "Under the High Patronage of Mr. Nicolas Sarkozy, President of the French Republic" but merely "under the patronage of Mrs. Valérie Pécresse, Higher Education and Research Minister, and Mrs. Christine Albanel, Culture and Communication Minister". However, other French events have been held "under the high patronage" of mere ministers, so apparently the rule is that the top patron is the high patron, and the others are mere unmodified patrons.
The corresponding expressions in some other languages seem to be "sotto l'alto patronato" (Italian, 186K ghits); "sous le haut patronage" (French, 100K ghits); "com o alto patrocinio" (Portuguese, 54.1K ghits); "con el alto patrocinio" (Spanish, 649 ghits); "unter der hohen Schirmherrschaft" (German, 136 ghits).
I'm not sure why German and Spanish are so underserved with high-patronaged events. I'm also not clear on why Italian and French mostly have events "sotto" and "sous" X's high patronage, while Portuguese and Spanish have events "com" and "con" the corresponding quality. The web evidence:
|sous le haut patronage||
|avec le haut patronage||
|sotto l'alto patronato||
|con le haut patronato||
|debaixo do alto patrocinio||
|com o alto patrocinio||
|debajo del alto patrocinio||
|con el alto patrocinio||
|under the high patronage||
|with the high patronage||
Perhaps I've guessed wrong about what the corresponding forms should be.
[Update — a comment below points out that "bajo el alto patricinio" has 766 hits, so I did guess wrong at least once.]