The Oxford English Dictionary (OED) is widely regarded as the accepted authority on the English language, serving as a guide to the meaning, history, and pronunciation of 600,000 words from across the English-speaking world.

Dictionary of Old English Corpus an online database consisting of at least one copy of every surviving Old English . In some cases, more than one copy is included, if it is significant because of dialect or date. There are 3037 texts in the corpus. Dates of Coverage: Last updated in 2009.

Dictionary of Old English: A to G Online Defines vocabulary of the first six centuries of the English language drawing on as wide a range of texts -- in date, dialect and genre -- as possible. Also provides a listing in a simplified paradigmatic order of every spelling which is attested for a word in the Electronic Corpus frequency counts for each word usage labels where they are statistically significant and exhaustive citation for all words of twelve or fewer occurrences. Complements the Middle English Dictionary (which covers the period 1100 - 1500 A.D.) and the Oxford English Dictionary (which documents the development of the English language to the present), the three together providing a full description of the vocabulary of English Dates of Coverage:The first six centuries (600 - 1150 A.D.) of the English language

Middle English Compendium A compilation of the Middle English Dictionary, a HyperBibliography of Middle English prose and verse, based on the MED bibliographies, and a Corpus of Middle English Prose and Verse, as well as links to an associated network of electronic resources. Dates of Coverage: Last updated in 2006

Early English Books Online (EEBO) covers many subject areas, including: English literature, history, philosophy, linguistics, theology, music, fine arts, education, mathematics, and science. Starting with the first book published in English through the age of Spenser and Shakespeare, this is an electronic collection of 125,000 titles listed in Pollard & Redgrave's Short-Title Catalogue (1475-1640) and Wing's Short-Title Catalogue (1641-1700) and their revised editions, as well as the Thomason Tracts (1640-1661) collection and the Early English Books Tract Supplement Dates of Coverage: Varies by publication

Patrologia Latina Database Electronic version of the first edition of Jacques-Paul Migne's Patrologia Latina, published between 1844 and 1855, and the four volumes of indexes published between 1862 and 1865. Contains the complete Patrologia Latina, including all prefatory material, original texts, critical apparatus and indexes. Migne's column numbers, essential references for scholars, are included. Dates of Coverage: Comprises the works of the Church Fathers from Tertullian in 200 AD to the death of Pope Innocent III in 1216