Crossword Puzzle Ruler of the past

Clue: Ruler of the past

Treasury offering of the past (EBOND with 5 letters)
River past Thebes (NILE with 4 letters)
Gets past a last difficulty ... or a hint to this puzzle's theme (ROUNDSTHECORNER with 15 letters)
Offspring of Bold Ruler and Somethingroyal (SECRETARIAT with 11 letters)
Mideast ruler of years past (SHAH with 4 letters)
Rulers of the past (SHAHS with 5 letters)
Theater offering (e.g. DRAMA with 5 letters)
Theater offering, sometimes (DRAMA with 5 letters)
Theater offerings (e.g. DRAMAS with 6 letters)
Movie theater offering (FEATUREFILM with 11 letters)