Back in the 1890s, Balliol was one of the few colleges to take on what were then called 'black' undergraduates (in truth, the majority were from India). Trinity was very proud of its all-white student body, and took to chanting 'Balliol, Balliol, bring out your black men' etc, as well as other equally witty racist epithets.
It was, however, noticed by a certain contingent at Balliol that Trinity had, in fact, taken on a certain Arthur Mario Agricola Collier Galetti-di-Cadilhac - apparently a rather swarthy Italian guy, nicknamed by some Balliolites as 'Gordouli' - after a popular brand of Egyptian cigarettes, it seems...
A song began, and continues to this day - 'The Gordouli'. A light-hearted joke at Trinity's hypocritical racism.