Zacchaeus (Greek: Ζακχαῖος, Zakchaios; Hebrew: זכי, which means pure and righteous one ), according to chapter 19 of the Gospel of Luke, was a superintendent of customs; a chief tax-gatherer (Latin: publicanus) at Jericho (Luke 19:1-10). Tax collectors were often corrupt, and hated by many of their fellow Jews, who saw them as traitors for working for the Roman Empire.
Because the lucrative production and export of balsam was centered in Jericho, his position would have carried both importance and wealth. In the account, he arrived before the crowd who were later to meet with Jesus, who was passing through Jericho on his way to Jerusalem. Described as a short man, Zacchaeus climbed up a sycamore fig tree so that he might be able to see Jesus. When Jesus reached the spot he looked up into the branches, addressed Zacchaeus by name, and told him to come down, for he intended to visit his house. The crowd was shocked that Jesus, a Jew, would sully himself by being a guest of a tax collector.
Moved by the audacity of Jesus' undeserved love and acceptance, Zacchaeus publicly repented acts of corruption and vowed to make restitution for them, and held a feast at his house.
At Er-riha (Jericho) there is a large, venerable looking square tower, which by tradition is named the House of Zacchaeus.
According to Clement of Alexandria, in his book Stromata, Zacchaeus was surnamed Matthias by the apostles, and took the place of Judas Iscariot after Jesus' ascension. Luke told us that Matthias in the beginning was with Jesus since the baptism of John (Acts 1:21-23). John also told us that later many of his disciples turned back and no longer followed him (John 6:60-66). The later Apostolic Constitutions identify "Zacchaeus the Publican" as the first bishop of Caesarea (7.46).
In Eastern Orthodox and Greek-Catholic Churches of Slavic tradition, the Gospel account of Zacchaeus is read on the last Sunday preceding the liturgical preparation for Great Lent, for which reason that Sunday is known as "Zacchaeus Sunday." It is the very first commemoration of a new Paschal cycle. The account was chosen to open the Lenten season because of two exegetical aspects: Jesus' call to Zacchaeus to come down from the tree (symbolizing the divine call to humility), and Zacchaeus' subsequent repentance.
In the Eastern churches of Greek/Byzantine tradition, Zacchaeus Sunday may fall earlier than the Sunday before the Pre-Lenten season.
The story of Zacchaeus is used by some to illustrate  the saying of Jesus: "Blessed are the pure of heart, For they shall see God" Matthew 5:8, because the name Zacchaeus means pure. Zacchaeus also becomes a contrast of character with the Rich Young Ruler Luke 18:-23. Both Zacchaeus and the Rich Young Ruler were wealthy men, but one felt a self-righteousness and would not give up his possessions, the other gave half his possessions to feed the poor. 
- http://cf.blueletterbible.org/lang/lexicon/Lexicon.cfm?Strongs=H2140&t=kjv Strongs Lexicon on the Blue Letter Bible website
- Morris, Leon. Luke: An Introduction and Commentary, page 297. Wm. B. Eerdmans, 1988.
- Stier, Rudolf Ewald. The Words of the Lord Jesus. Trans. William Burt Pope. Page 314. Sheldon & co., 1859.
- Pastor Doug Bachelor, Study on the Wisdom of Jesus' teachings
- A Contrast of Character | Zacchaeus and the Rich Young Ruler
|Wikimedia Commons has media related to Zacchaeus.|
|Bishop of Caesarea
Cornelius (possibly Cornelius the Centurion)