Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. This is an index of Welsh peers whose primary peerage, life peerage, and baronetcy titles includes a Welsh place-name origin or its territorial qualification is within the historic counties of Wales. Welsh-titled peers hold their titles from a variety of sources. After Llywelyn ap Gruffydd of the House of Aberffraw, the last Welsh Prince of Wales, was killed during the Edwardian Conquest in 1282, the Principality of Wales was divided into English-style counties. Many of the former native titles were abolished, with some of the native Welsh lords given English titles in exchange for their loyalty. However, Welsh Law remained in force in the principality for civil cases, including for inheritance. However, Edward I did reform Welsh succession to male preference primogeniture, an amendment which facilitated the inheritance of English marcher lords to Welsh lands.