Sigillum Altaris
(seal of the altar). "The authentic mark of an altar was its five crosses; and there was a small stone called sigillum altaris, by which the aperture for the insertion of relics was closed up by mortar tempered in holy water" (Fosbrooke).
The Cyclopedia of Biblical, Theological, and Ecclesiastical Literature was edited by John McClintock and James Strong. It contains nearly 50,000 articles pertaining to Biblical and other religious literature, people, creeds, etc. It is a fantastic research tool for broad Christian study.
John McClintock was born October 27, 1814 in Philadelphia to Irish immigrants, John and Martha McClintock. He began as a clerk in his father's store, and then became a bookkeeper in the Methodist Book Concern in New York. Here he converted to Methodism and considered joining the ministry. McClintock entered the University of Pennsylvania in 1832 and graduated with high honors three years later. Subsequently, he was awarded a doctorate of divinity degree from the same institution in 1848.WikipediaRead More