For a complete picture of the history of star formation in the Magellanic Clouds, knowledge about the age distribution as well as the surface distribution of the intermediate-age and the oldest stars is needed. The evolved red giants are the most luminous in these generations and have therefore attracted most interest and contributed much to our understanding of the stellar evolution. It is now possible to reach stars as faint as V = 24 mag, so that main-sequence field stars much older than 3–4 Gyr may be observed in the Clouds. Their importance for solving star formation problems will increase as observations of still fainter stars have become available (using the HST). A brief summary of what is known today is therefore appropriate.

Main-sequence stars

A large number of colour–magnitude diagrams reaching main-sequence stars below Mv = 2 mag have been presented for regions in many parts of the LMC. The bulk of stars appear to have formed about 3–4 Gyr ago (Butcher 1977, Stryker 1984, Hardy et al. 1984, Hodge 1987). Some doubts have been expressed about the reliability of the photographic photometry on which these results were based, as well as on the age calibrators used, but the overall results have been confirmed (Vallenari et al. 1994c). The main-sequence differential luminosity functions for seven LMC fields are compared in Fig. 7.1.