Phonetic transliteration of a foreign name with the structure 'Is-be(y)'.
伊斯 (Yīsī) is the standard rendering of 'Is-' (as in
伊斯兰 Islam,
伊斯坦布尔 Istanbul);
贝 (bèi) renders '-bey' or '-be'. Most likely refers to French painter Jean-Baptiste Isabey (1767-1855) or his son Eugène Isabey, in arts contexts.
