This is the Snakeshead Fritillary (fritillary just meaning chequered, describing the tessellated patterning on the flower) growing from the Slovak Republic to Poland through to central France and southern England. Once widespread in England, and a regular feature in Elizabethan gardens, many of the damp meadows in which it once grew have been ploughed or drained, and the flowers have been lost. Some couple of dozen sites remain, and it is in similar conditions that it likes to grow in our gardens. It grows easily in grass or drained but damp soil in the sun or half shade, but does not like being dried out completely. The leaves are narrow, and can be lost in grass, but the flowers are beautiful, square-shouldered bells in pink, mauve and darker purples, lightly chequered. Inside they are paler, but more splashed with shining green. They ought to be planted in late summer or early autumn, to allow rooting to start before the soils cool. The bulbs should not be disturbed. Higher rainfall in the spring will encourage them rather than years of winter drought.
Plant in small unregimented drifts of 5-7 bulbs 4" apart and about 4" deep at variable spacing in heavier soils in the open or slight shade, perhaps in rough grass. They like cool damp growing conditions in spring before a drier summer rest.