OT: Was Latin /r/ trilled?

[Douglas G. Wilson]

>I've been asked whether the ancient Romans trilled the sound /r/.

It seems to be a popular notion that they did. This is what I was taught in
my ('classical', not ecclesiastical) Latin course, back in the day ...
although pronunciation with English-type "r" was usual (and tolerated) in
practice. Several Web sites assert this ('alveolar trill', I think they say
usually ... generally likened to the "r" ("rr") in Spanish or to the "r" in
Italian).

I can't find any reasoning supporting the assertion, in a brief glance at
immediately available general reference books and Web sites: is it just a
guess based on the later Romance languages?

-- Doug Wilson