Old Bob
... that Abraham Lincoln probably named his horse Old Bob to differentiate it from his son, "Young Bob"?
... that <a href="./Abraham_Lincoln" id="mwA-I" rel="mw:WikiLink" title="Abraham Lincoln">Abraham Lincoln</a> probably named his horse <b id="mwA-M"><a href="./Old_Bob" id="mwA-Q" rel="mw:WikiLink" title="Old Bob">Old Bob</a></b> to differentiate it from his son, "<a class="mw-redirect" href="./Robert_Lincoln" id="mwA-U" rel="mw:WikiLink" title="Robert Lincoln">Young Bob</a>"?