Each spring for a period of weeks the imperial gardens were filled with prize tulips (Turkish, Dutch, Iranian), all of them shown to their best advantage. Tulips whose petals had flexed wide were held shut with fine threads hand-tied. Most of the bulbs had been grown in place, but these were supplemented by thousands of cut stems held in glass bottles; the scale of the display was further compounded by mirrors placed strategically around the garden. Each variety was marked with a label made from silver filigree. In place of every fourth flower a candle, its wick trimmed to tulip height, was set into the ground. Songbirds in gilded cages supplied the music, and hundreds of giant tortoises carrying candles on their backs lumbered through the gardens, further illuminating the display. All the guests were required to dress in colors that flattered those of the tulips. At the appointed moment a cannon sounded, the doors to the harem were flung open, and the sultan's mistresses stepped into the garden led by eunuchs bearing torches. The whole scene was repeated every night for as long as the tulips were in bloom, for as long as Sultan Ahmed managed to cling to his throne.