badly from Latin mille thousand, after myriad
1851 - as per E-NED and The Historical Thesaurus of English;
(see Example below for 1841 example)
From: Journal of the Asiatic Society of Bengal,
Volume XIX, 1850, Printed 1851
From: The Oberlin Evangelist:
A Semi-Monthly Periodical, Devoted to the Promotion of Religion.
Volume III, 1841