G.E. Bosworth, The new Islamic dynasties, Edinburgh, 1996. Lastly, since so much concerning the history of the Seljukids has appeared in learned periodicals, recourse must be made to the essential guide to these, Index Islamicus. The first volume, compiled by the late J.D. Pearson, and covering the years 1906-55, was published at Cambridge in 1958. The latest pair of volumes in the series are Index Islamicus 1981-1985 (ed. G.J. Roper), London 1991. The most helpful maps will be found in Donald Edgar Pitcher, An historical geography of the Ottoman Empire, Leiden, 1972, although the bulk of the work deals with a later period; the Index is useful for Byzantine/Turkish identification. William C. Brice, An historical atlas of Islam, Leiden, 1981, is also useful.