(1323 — 1336), brother of Michael III, removed by Ivan Alexander. Ivan IV Asen, prince and co-tsar (1337 — 1349), son of tsar Ivan Alexander Michael IV Asen, prince and co-tsar (1337 — 1349), son of tsar Ivan Alexander Shishman II, claimant in exile Ivan Sratsimir, tsar (1356 — 1365), son of Bulgarian tsar Ivan Alexander Hungarian rule (1365 — 1369). Sratsimir, tsar (1369 — 1396) second reign Constantine II, tsar (1396 — 1422) Ottoman conquest References Further reading