Excerpt:
In 1853, the British explorer Sir Richard Francis Burton visited Mecca. Since Mecca was and is off limits to non-Muslims on pain of dearth, Burton passed himself off as a Muslim by undergoing circumcision and disguising himself as a Pashtun. "Nothing could save a European detected by the populace, or one who after pilgrimage declared himself an unbeliever," Burton wrote.
350 years earlier, the Italian adventurer Ludovico di Varthema became the first non-Muslim to enter Mecca since the Muslim conquest. Ludovico had enlisted as a mercenary and succeeded in passing as a Mamluk, one of the white slave soldiers of the Sultanate, who had been converted to Islam. Ludovico was eventually caught out as a Christian, but escaped after a love affair with one of the Sultan's wives.
Other Christians had visited Mecca, but always disguised as Muslims. The British cabin boy Joseph Pitts, captured by Muslim slavers and forcibly converted to Islam, visited Mecca, before managing to return home and return to his religion. Similar accounts were told by other European Christian slaves.