Per the same Ottoman decline thesis as first formulated by Bernard Lewis (see below), from 1699 onwards, the Ottoman Empire began to lose territory over the course of the next two centuries due to internal stagnation, costly defensive wars, European colonialism, and nationalist revolts among its multiethnic subjects. In any case, decline was evident to the empire’s leaders by the early 19th century (see below); beginning in the early part of that century, numerous administrative reforms were implemented in an attempt to forestall the decline of the empire, with varying degrees of success. The gradual weakening of the Ottoman Empire gave rise to the Eastern Question in the mid-19th century.