▁Gab al as ▁or ▁by ▁an ▁un named ▁relative . ▁John ▁succeeded ▁his ▁brother ▁after ▁the ▁latter ' s ▁death ▁som etime ▁in ▁the ▁early ▁ 1 2 4 0 s . ▁Un like ▁Leo , ▁who ▁had ▁exerc ised ▁almost ▁independent ▁authority ▁and ▁even ▁concluded ▁treat ies ▁of ▁his ▁own , ▁John ▁was ▁dependent ▁on ▁the ▁Empire ▁of ▁N ica ea . ▁While ▁Leo ▁held ▁the ▁lo fty ▁title ▁of ▁" Ca esar " ▁and ▁claimed ▁to ▁rule ▁several ▁A ege an ▁islands , ▁John ▁is ▁only ▁att ested ▁as ▁" Master ▁of ▁Rh odes ". ▁A ▁letter ▁of ▁King ▁Henry ▁I ▁of ▁Cy pr us , ▁found ▁in ▁the ▁V at ican ▁Library , ▁appears ▁to ▁refer ▁to ▁John . ▁It ▁addresses ▁him ▁with ▁the ▁titles ▁that ▁he ▁received ▁from ▁the ▁N ica e an ▁em peror , ▁se b ast os ▁and ▁meg as ▁dou x , ▁and ▁indicates ▁that ▁he ▁was ▁an ▁imperial ▁relative ▁by ▁marriage ▁( g amb ros ), ▁probably ▁as ▁a ▁result ▁of ▁a ▁marriage ▁to ▁a ▁V at atz es ▁lady , ▁which ▁may ▁have ▁taken ▁place ▁already ▁before ▁Leo ' s ▁death . ▁ ▁Al most ▁nothing ▁else ▁is ▁known ▁of ▁him ▁and ▁his ▁rule ▁except ▁that ▁in ▁ 1 2 4 8 , ▁he ▁was ▁with ▁the ▁N ica e an ▁army ▁campaign ing ▁against ▁the ▁Latin ▁Empire ▁near ▁Nic om edia , ▁when ▁the ▁Gen o ese ▁suddenly ▁seized ▁Rh odes . ▁A ▁N ica e an ▁expedition , ▁under ▁the ▁p