Bernard of Clairvaux (1090-1153) was canonized in 1174 and made a "Doctor of the Church" in 1830. He is honored on August 20 in the calendars of the Roman Catholic, Episcopal, and ELCA Churches and on August 19 in the Lutheran Church Missouri Synod. So we can think about him on both days.
Here is a site that gives some background on Bernard: http://www.americancatholic.org/Features/Saints/saint.aspx?id=1113&calendar=1 and also http://www.christianitytoday.com/history/people/moversandshakers/bernard-of-clairvaux.html That second author comments: "It's hard to know how to characterize Bernard of Clairvaux. On the one hand, he is called the 'honey-tongued doctor' for his eloquent writings on the love of God. On the other hand, he rallied soldiers to kill Muslims. He wrote eloquently on humility; then again, he loved being close to the seat of power and was an adviser to five popes." Bernard joined the new community, the